AIM: To investigate the effect of polydatin (PD), a resveratrol glucoside, on mast cell degranulation and antiallergic activity. METHODS: After the rats were orally sensitized with ovalbumin (OVA) for 48 d and underwe...AIM: To investigate the effect of polydatin (PD), a resveratrol glucoside, on mast cell degranulation and antiallergic activity. METHODS: After the rats were orally sensitized with ovalbumin (OVA) for 48 d and underwent PD treatment for 4 d, all the rats were stimulated by 100 mg/mL OVA for24 h and then sacrificed for the following experiments. The small intestines from all the groups were prepared for morphology examination by hematoxylin and eosin staining. We also used a smooth muscle organ bath to evaluate the motility of the small intestines. The OVA-specific immunoglobulin E (IgE) production and interleu-kin-4 (IL-4) levels in serum or supernatant of intestinal mucosa homogenates were analyzed by enzyme-linked immunosorbent assay (ELISA). Using toluidine blue stain, the activation and degranulation of isolated rat peritoneal mast cells (RPMCs) were analyzed. Release of histamine from RPMCs was measured by ELISA, and regulation of PD on intracellular Ca 2+ mobilization was investigated by probing intracellular Ca 2+ with fluo-4 fluo-rescent dye, with the signal recorded and analyzed. RESULTS: We found that intragastric treatment with PD significantly reduced loss of mucosal barrier integrity in the small intestine. However, OVA-sensitization caused significant hyperactivity in the small intestine of allergic rats, which was attenuated by PD administration by 42% (1.26 ± 0.13 g vs OVA 2.18 ± 0.21 g, P < 0.01). PD therapy also inhibited IgE production (3.95 ± 0.53 ng/mL vs OVA 4.53 ± 0.52 ng/mL, P < 0.05) by suppressing the secretion of Th2-type cytokine, IL-4, by 34% (38.58 ± 4.41 pg/mLvs OVA 58.15 ± 6.24 pg/mL, P < 0.01). The ratio of degranulated mast cells, as indicated by vehicles (at least five) around the cells, dramatically increased in the OVA group by 5.5 fold (63.50% ± 15.51% vs phosphate-buffered saline 11.15% ± 8.26%, P < 0.001) and fell by 65% after PD treatment (21.95% ± 4.37% vs OVA 63.50% ± 15.51%, P < 0.001). PD mediated attenuation of mast cell degranulation was further confirmed by decreased histamine levels in both serum (5.98 ± 0.17 vs OVA 6.67 ± 0.12, P < 0.05) and intestinal mucosa homogenates (5.83 ± 0.91 vs OVA 7.35 ± 0.97, P < 0.05). Furthermore, we demonstrated that administration with PD significantly decreased mast cell degranulation due to reduced Ca 2+ influx through store-operated calcium channels (SOCs) (2.35 ± 0.39vs OVA 3.51 ± 0.38,P < 0.01).CONCLUSION: Taken together, our data indicate that PD stabilizes mast cells by suppressing intracellular Ca 2+ mobilization, mainly through inhibiting Ca 2+ entry via SOCs, thus exerting a protective role against OVA-sensitized food allergy.展开更多
The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central n...The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channelspecific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood–brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems.展开更多
AIM:To further investigate the important role of store-operated calcium channels(SOCs)in rat hepatocytes and to explore the effects of SOC blockers on hepatic ischemia-reperfusion injury(HIRI).METHODS:Using freshly is...AIM:To further investigate the important role of store-operated calcium channels(SOCs)in rat hepatocytes and to explore the effects of SOC blockers on hepatic ischemia-reperfusion injury(HIRI).METHODS:Using freshly isolated hepatocytes from a rat model of HIRI(and controls),we measured cyto-solic free Ca 2+concentration(by calcium imaging),net Ca 2+fluxes(by a non-invasive micro-test technique),the SOC current(I SOC;by whole-cell patch-clamp record-ing),and taurocholate secretion[by high-performance liquid chromatography and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays].RESULTS:Ca 2+oscillations and net Ca 2+fluxes medi-ated by Ca 2+entry via SOCs were observed in rat he-patocytes.I SOC was significantly higher in HIRI groups than in controls(57.0±7.5 pA vs 31.6±2.7 pA,P<0.05)and was inhibited by La 3+.Taurocholate secretion by hepatocytes into culture supernatant was distinctly lower in HIRI hepatocytes than in controls,an effect reversed by SOC blockers.CONCLUSION:SOCs are pivotal in HIRI.SOC blockers protected against HIRI and assisted the recovery of se-cretory function in hepatocytes.Thus,they are likely to become a novel class of effective drugs for prevention or therapy of HIRI patients in the future.展开更多
Type 2 diabetes mellitus(T2DM)is a prevalent metabolic disorder.Despite the availability of numerous pharmacotherapies,a range of adverse reactions,including hypoglycemia,gastrointestinal discomfort,and lactic acidosi...Type 2 diabetes mellitus(T2DM)is a prevalent metabolic disorder.Despite the availability of numerous pharmacotherapies,a range of adverse reactions,including hypoglycemia,gastrointestinal discomfort,and lactic acidosis,limits their patient applicability and long-term application.Therefore,it is necessary to screen novel therapeutic drugs for T2DM treatment that have high efficacy but few adverse effects.AMP-activated protein kinase(AMPK)stands out as one of the most powerful targets for T2DM treatment.It can be activated through energysensing or calcium signaling.Medications that activate AMPK through the energy-sensing mechanism exhibit remarkable potency,but they are accompanied by lactic acidosis,carrying an alarmingly high mortality rate.Interestingly,medications that activate AMPK through calcium signaling,such as gliclazide,seldom induce lactic acidosis.However,the efficacy of gliclazide is much lower than metformin.Therefore,it is necessary to explore targets that activate AMPK via calcium signaling to avoid lactic acidosis while maintaining high potency.Ion channels are the main controller of intracellular calcium flow.Specific agonists and inhibitors targeting ion channels have been reported to activate AMPK.In this review,we will summarize the structure and function of calcium-permeable ion channels and discuss the potential of targeting these calcium channels for T2DM treatment.展开更多
Aim: To study the effects of rhynchophylline (Rhy) on the L type calcium channels in freshly dissociated cortical neurons of Wistar rats during acute hypoxia. Methods: Cell attached configuration of patch clamp tech...Aim: To study the effects of rhynchophylline (Rhy) on the L type calcium channels in freshly dissociated cortical neurons of Wistar rats during acute hypoxia. Methods: Cell attached configuration of patch clamp technique. L type calcium channel was activated by stepping from 40 mV to 0 mV. Results: The results showed that the L type calcium channels of cortical neurons were activated by acute hypoxia. The mean open time of the channel was increased, the mean close time decreased and the open state probability raised during acute hypoxia. Rhy (15 and 30μmol·L -1 ) in concentration dependent manner blocked activity of the channels. The drug shortened the mean open time of the channels from 8 87 ms to 3 03 ms and 2 23 ms ( P 【0 001), prolonged the mean close time from 9 23 ms to 38 84 ms and 54 43 ms ( P 【0 001), and decreased the open state probability from 0 142 to 0 031 and 0 025 ( P 【0 001) under the hypoxia condition, respectively. The effects of Rhy were similar to but weaker than those of verapamil (15 μmol·L -1 ). Conclusion: The study confirmed that Rhy has the blockade effects on L type calcium channels in cortical neurons of rats during hypoxia, by which it protects the brain from hypoxic injury.展开更多
Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter...Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear; however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers.展开更多
AIM:To investigate the effect of hydrogen sulfide(H2S)on smooth muscle motility in the gastric fundus.METHODS:The expression of cystathionineβ-synthase(CBS)and cystathionineγ-lyase(CSE)in cultured smooth muscle cell...AIM:To investigate the effect of hydrogen sulfide(H2S)on smooth muscle motility in the gastric fundus.METHODS:The expression of cystathionineβ-synthase(CBS)and cystathionineγ-lyase(CSE)in cultured smooth muscle cells from the gastric fundus was examined by the immunocytochemistry technique.The tension of the gastric fundus smooth muscle was recorded by an isometric force transducer under the condition of isometric contraction with each end of the smooth muscle strip tied with a silk thread.Intracellular recording was used to identify whether hydrogen sulfide affects the resting membrane potential of the gastric fundus in vitro.Cells were freshly separated from the gastric fundus of mice using a variety of enzyme digestion methods and whole-cell patch-clamp technique was used to find the effects of hydrogen sulfide on voltage-dependent potassium channel and calcium channel.Calcium imaging with fura-3AM loading was used to investigate the mechanism by which hydrogen sulfide regulates gastric fundus motility in cultured smooth muscle cells.RESULTS:We found that both CBS and CSE were expressed in the cul tured smooth muscle cel ls from the gastric fundus and that H2S increased the smooth muscle tension of the gastric fundus in mice at low concentrations.In addition,nicardipine and aminooxyacetic acid(AOAA),a CBS inhibitor,reduced the tension,whereas Nω-nitro-L-arginine methyl ester,a nonspecific nitric oxide synthase,increased the tension.The AOAA-induced relaxation was significantly recovered by H2S,and the Na HS-induced increase in tonic contraction was blocked by 5 mmol/L4-aminopyridine and 1μmol/L nicardipine.Na HS significantly depolarized the membrane potential and inhibited the voltage-dependent potassium currents.Moreover,Na HS increased L-type Ca2+currents and caused an elevation in intracellular calcium([Ca2+]i).CONCLUSION:These findings suggest that H2S may be an excitatory modulator in the gastric fundus in mice.The excitatory effect is mediated by voltagedependent potassium and L-type calcium channels.展开更多
Objective Formaldehyde at high concentrations is a contributor to air pollution. It is also an endogenous metabolic product in cells, and when beyond physiological concentrations, has pathological effects on neurons. ...Objective Formaldehyde at high concentrations is a contributor to air pollution. It is also an endogenous metabolic product in cells, and when beyond physiological concentrations, has pathological effects on neurons. Formaldehyde induces mis-folding and aggregation of neuronal tau protein, hippocampal neuronal apoptosis, cognitive impairment and loss of memory functions, as well as excitation of peripheral nociceptive neurons in cancer pain models. Intracellular calcium （[Ca2＋]i） is an important intracellular messenger, and plays a key role in many pathological processes. The present study aimed to investigate the effect of formaldehyde on [Ca2＋]i and the possible involvement of N-methyl-D-aspartate receptors （NMDARs） and T-type Ca2＋ channels on the cell membrane. Methods Using primary cultured hippocampal neurons as a model, changes of [Ca2＋]i in the presence of formaldehyde at a low concentration were detected by confocal laser scanning microscopy. Results Formaldehyde at 1 mmol/L approximately doubled [Ca2＋]i. （2R）-amino-5-phosphonopentanoate （AP5, 25 μmol/L, an NMDAR antagonist） and mibefradil （MIB, 1 μmol/L, a T-type Ca2＋ channel blocker）, given 5 min after formaldehyde perfusion, each partly inhibited the formaldehyde-induced increase of [Ca：＋]i, and this inhibitory effect was reinforced by combined application of AP5 and MIB. When applied 3 min before formaldehyde perfusion, AP5 （even at 50μmol/L） did not inhibit the formaldehyde-induced increase of [Ca2＋]i, but MIB （1 μmol/L） significantly inhibited this increase by 70%. Conclusion These results suggest that formaldehyde at a low concentration increases [Ca2＋]i in cultured hippocampal neurons; NMDARs and T-type Ca2＋ channels may be involved in this process.展开更多
AIM： To study the effects of hepatic ischemia/ reperfusion （I/R） injury on store-operated calcium channel （SOC） currents （Isoc） in freshly isolated rat Kupffer cells, and the effects of Ca^2＋ channel blockers,...AIM： To study the effects of hepatic ischemia/ reperfusion （I/R） injury on store-operated calcium channel （SOC） currents （Isoc） in freshly isolated rat Kupffer cells, and the effects of Ca^2＋ channel blockers, 2-aminoethoxydiphenyl borate （2-APB）, SK＆F96365, econazole and miconazole, on Isoc in isolated rat Kupffer cells after hepatic I/R injury.METHODS： The model of rat hepatic I/R injury was established. Whole-cell patch-clamp techniques were performed to investigate the effects of 2-APB, SK＆F96365, econazole and miconazole on Isoc in isolated rat Kupffer cells after hepatic I/R injury.RESULTS： I/R injury significantly increased Isoc from -80.4±25.2pA to -159.5±34.5pA （^bp 〈 0.01, n = 30）. 2-APB （20, 40, 60, 80, 100 pmol/L）, SK＆F96365 （5, 10, 20, 40, 50 pmol/L）, econazole （0.1, 0.3, 1, 3, 10 μmol/L） and miconazole （0.1, 0.3, 1, 3, 10 μmol/L） inhibited Isoc in a concentration-dependent manner with IC50 of 37.41 μmol/L （n = 8）, 5.89 μmol/L （n = 11）, 0.21 μmol/L （n = 13）, and 0.28 μmol/L （n = 10）. The peak value of Isoc in the I-V relationship was decreased by the blockers in different concentrations, but the reverse potential of Isoc was not transformed. CONCLUSION： SOC is the main channel for the influx of Ca^2＋ during hepatic I/R injuries. Calcium channel blockers, 2-APB, SK＆F96365, econazole and miconazole,have obviously protective effects on I/R injury, probably by inhibiting Isoc in Kupffer cells and preventing the activation of Kupffer cells.展开更多
Neuroglial cells are homeostatic neural cells. Generally, they are electrically non-excitable and their activation is associated with the generation of complex intracellular Ca^2＋ signals that define the ＂Ca^2＋ exc...Neuroglial cells are homeostatic neural cells. Generally, they are electrically non-excitable and their activation is associated with the generation of complex intracellular Ca^2＋ signals that define the ＂Ca^2＋ excitability＂ of glia. In mammalian glial cells the major source of Ca^2＋ for this excitability is the lumen of the endoplasmic reticulum （ER）, which is ultimately （re）filled from the extracellular space. This occurs via store-operated Ca^2＋ entry （SOCE） which is supported by a specific signaling system connecting the ER with plasmalemmal Ca^2＋ entry. Here, emptying of the ER Ca^2＋ store is necessary and sufficient for the activation of SOCE, and without Ca^2＋ influx via SOCE the ER store cannot be refilled. The molecular arrangements underlying SOCE are relatively complex and include plasmalemmal channels, ER Ca^2＋ sensors, such as stromal interaction molecule, and possibly ER Ca^2＋ pumps （of the SERCA type）. There are at least two sets of plasmalemmal channels mediating SOCE, the Ca2＊-release activated channels, Orai, and transient receptor potential （TRP） channels. The molecular identity of neuroglial SOCE has not been yet identified unequivocally. However, it seems that Orai is predominantly expressed in microglia, whereas astrocytes and oligodendrocytes rely more on TRP channels to produce SOCE. In physiological conditions the SOCE pathway is instrumental for the sustained phase of the Ca^2＋ signal observed following stimulation of metabotropic receptors on glial cells.展开更多
Iron overload can lead to iron deposits in many tissues,particularly in the heart.It has also been shown to be associated with elevated oxidative stress in tissues.Elevated cardiac iron deposits can lead to iron overl...Iron overload can lead to iron deposits in many tissues,particularly in the heart.It has also been shown to be associated with elevated oxidative stress in tissues.Elevated cardiac iron deposits can lead to iron overload cardiomyopathy,a condition which provokes mortality due to heart failure in iron-overloaded patients.Currently,the mechanism of iron uptake into cardiomyocytes is still not clearly understood.Growing evidence suggests L-type Ca2+channels(LTCCs)as a possible pathway for ferrous iron(Fe2+)uptake into cardiomyocytes under iron overload conditions.Nevertheless,controversy still exists since some findings on pharmacological interventions and those using different cell types do not support LTCC’s role as a portal for iron uptake in cardiac cells.Recently,T-type Ca2+channels (TTCC)have been shown to play an important role in the diseased heart.Although TTCC and iron uptake in cardiomyocytes has not been investigated greatly,a recent finding indicated that TTCC could be an important portal in thalassemic hearts.In this review,comprehensive findings collected from previous studies as well as a discussion of the controversy regarding iron uptake mechanisms into cardiomyocytes via calcium channels are presented with the hope that understanding the cellular iron uptake mechanism in cardiomyocytes will lead to improved treatment and prevention strategies,particularly in iron-overloaded patients.展开更多
In the current study,we sought to investigate whether T-type Ca^(2+)channels(TCCs)in the brain are involved in generating post-anesthetic hyperexcitatory behaviors(PAHBs).We found that younger rat pups(postnatal days ...In the current study,we sought to investigate whether T-type Ca^(2+)channels(TCCs)in the brain are involved in generating post-anesthetic hyperexcitatory behaviors(PAHBs).We found that younger rat pups(postnatal days 9-11)had a higher incidence of PAHBs and higher PAHB scores than older pups(postnatal days16-18)during emergence from sevoflurane anesthesia.The power spectrum of the theta oscillations(4 Hz-8 Hz)in the prefrontal cortex was significantly enhanced in younger pups when PAHBs occurred,while there were no significant changes in older pups.Both the power of theta oscillations and the level of PAHBs were significantly reduced by the administration of TCC inhibitors.Moreover,the sensitivity of TCCs in the medial dorsal thalamic nucleus to sevoflurane was found to increase with age by investigating the kinetic properties of TCCs in vitro.TCCs were activated by potentiated GABAergic depolarization with a sub-anesthetic dose of sevoflurane(1%).These data suggest that(1)TCCs in the brain contribute to the generation of PAHBs and the concomitant electroencephalographic changes;(2)the stronger inhibitory effect of sevoflurane contributes to the lack of PAHBs in older rats;and(3)the contribution of TCCs to PAHBs is not mediated by a direct effect of sevoflurane on TCCs.展开更多
LTCCS ARE IMPLICATED IN THE PATHOLOGY OF BIPOLAR DISORDER Bipolar disorder (BPD) is a common mental illness with significant morbidity and mortality.1 Although evidence have suggested changes in oxidative stress, dopa...LTCCS ARE IMPLICATED IN THE PATHOLOGY OF BIPOLAR DISORDER Bipolar disorder (BPD) is a common mental illness with significant morbidity and mortality.1 Although evidence have suggested changes in oxidative stress, dopamine and inflammation in BPD, it is hard to define the aetiological mechanism of BPD clearly. Recently, some but not all candidate gene association studies, family-based association studies, linkage studies, genome-wide association studies (GWASs) and meta-analyses showed that mutation of L-type voltage-gated calcium chan? nels (LTCCs) gene CACNAlCis implicated in the mechanism of BPD.'-8 These findings support the possibility that BPD might have calcium channelopathy.展开更多
The acrosome reaction （AR）, an absolute requirement for spermatozoa and egg fusion, requires the influx of Ca2＋ into the spermatozoa through voltage-dependent Ca2＋ channels and store-operated channels. Maitotoxin ...The acrosome reaction （AR）, an absolute requirement for spermatozoa and egg fusion, requires the influx of Ca2＋ into the spermatozoa through voltage-dependent Ca2＋ channels and store-operated channels. Maitotoxin （MTx）, a Ca2＋-mobilizing agent, has been shown to be a potent inducer of the mouse sperm AR, with a pharmacology similar to that of the zona pellucida （ZP）, possibly suggesting a common pathway for both inducers. Using recombinant human ZP3 （rhZP3）, mouse ZP and two MTx channel blockers （U73122 and U73343）, we investigated and compared the MTx- and ZP-induced ARs in human and mouse spermatozoa. Herein, we report that MTx induced AR and elevated intracellular Ca2＋ （[Ca2＋]~） in human spermatozoa, both of which were blocked by U73122 and U73343. These two compounds also inhibited the MTx-induced AR in mouse spermatozoa. In disagreement with our previous proposal, the AR triggered by rhZP3 or mouse ZP was not blocked by U73343, indicating that in human and mouse spermatozoa, the AR induction by the physiological ligands or by MTx occurred through distinct pathways. U73122, but not U73343 （inactive analogue）, can block phospholipase C （PLC）. Another PLC inhibitor, edelfosine, also blocked the rhZP3- and ZP-induced ARs. These findings confirmed the participation of a PLC-dependent signalling pathway in human and mouse zona protein-induced AR. Notably, edelfosine also inhibited the MTx-induced mouse sperm AR but not that of the human, suggesting that toxin-induced AR is PLC-dependent in mice and PLC-independent in humans.展开更多
Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thal...Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thaliana,the OSCA family has been identified as mechanically activated ion channels that respond to osmotic stress by allowing calcium ions to enter the cell.This influx increases the cytoplasmic calcium concentration,triggering osmotic stress-induced signal transduction cascades in plants.In this study,we determined the structures of OSCA2.2 and OSCA3.1 via cryoelectron microscopy(cryo-EM).Both proteins form homodimers consisting of 11 transmembrane helices(TM1–11).The ion conduction pathway is formed by TM4–8.Despite belonging to the same family,OSCA2.2 and OSCA3.1 exhibit notable structural variations.Structural analysis revealed that both OSCA2.2 and OSCA3.1 exhibit a closed conformation.We also conducted functional studies on OSCA proteins via electrophysiological experiments and confirmed the role of key amino acids in the process of ion permeation.展开更多
In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium. Attached cells when stimulated with high potassium secreted la...In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium. Attached cells when stimulated with high potassium secreted large amount of amylase. High potassium-induced secretion was dependent both on the concentration of potassium and duration of stimulation. High potassium induced increases in intracellular calcium were inhibited by voltage-dependent calcium channel antagonists with an order of potency as follows: nifedipine > ω-agatoxin IVA > ω-conotoxin GVIA. In contrast, the L-type calcium channel antagonist nifedipine almost completely inhibited potassium-induced amylase secretion, whereas the N-type channel antagonist ω-conotoxin GVIA was without effect. The P-type channel antagonist ω-agatoxin IVA had a small inhibitory effect, but this inhibition was not significant at the level of amylase secretion. In conclusion, the AR4-2J cell line possesses different voltage-dependent calcium channels (L, P,N) with the L-type predominantly involved in depolarization induced amylase secretion.展开更多
Objective:To evaluate spasmolytic mechanisms of aqueous and methanolic extracts from Distemonanthus benthamianus trunk-bark.Methods:Spasmolytic activities of extracts were evaluated in vitro on spontaneous and potassi...Objective:To evaluate spasmolytic mechanisms of aqueous and methanolic extracts from Distemonanthus benthamianus trunk-bark.Methods:Spasmolytic activities of extracts were evaluated in vitro on spontaneous and potassium chloride-induced jejunum contractions,or against cholinergic[acetylcholine(0.3μmol/L)]stimulations.High performance liquid chromatography analysis of both extracts was performed in reference to standard compounds.Results:Extracts developed concentration-dependent inhibitory activities.The methanolic extract,which revealed better activity,produced spasmolytic and myorelaxant effects at concentrations of 0.01-0.30 mg/mL with EC(50)of 0.06 and 0.09 mg/mL(95%CI:0.03-0.3 mg/mL),respectively.Its anticholinergic effect was obtained at the same concentrations with EC(50)of 0.11 mg/mL(95%CI:0.03-0.3 mg/mL).Chromatograms showed the presence of gallic acid in both extracts,rutin being only detected in the aqueous extract.Conclusions:Distemonanthus benthamianus extracts exhibit verapamil and atropine-like activities,thus highlighting calcium channels and muscarinic receptors blocking potentials,which may be conveyed by some phenolic compounds.These results confirm the antidiarrheal activity of Distemonanthus benthamianus extracts.展开更多
The effects of hepatic ischemia/reperfusion (I/R) injuries on hepatocellular viability and store-operated calcium current (Isoc) in isolated rat hepatocytes and the effects of 2-APB on store-operated calcium current (...The effects of hepatic ischemia/reperfusion (I/R) injuries on hepatocellular viability and store-operated calcium current (Isoc) in isolated rat hepatocytes and the effects of 2-APB on store-operated calcium current (Isoc) in isolated rat hepatocytes after hepatic ischemia/reperfusion injuries were studied. Hepatic ischemia and reperfusion injury model was established and whole cell patch-clamp techniques were used to investigate the effects of 2-APB on Isoc. The results showed that ischemia/reperfusion injuries could significantly reduce hepatocellular viability and further increase Isoc in hepatocytes and 2-APB (20, 40, 60, 80, 100 μmol/L) produced a concentration-dependent decrease of Isoc with IC 50 value of 64.63±10.56 μmol/L (n=8). It was concluded that ischemia/reperfusion injuries could reduce hepatocellular viability, probably through increased Isoc in hepatocytes and 2-APB had a protective effect on ischemia/reperfusion-induced liver injury, probably though inhibiting Isoc.展开更多
Spontaneous, rhythmical contractions, or vasomotion, can be recorded from cerebral vessels under both normal physiological and pathophysiological conditions. We investigated the cellular mechanisms underlying vasomoti...Spontaneous, rhythmical contractions, or vasomotion, can be recorded from cerebral vessels under both normal physiological and pathophysiological conditions. We investigated the cellular mechanisms underlying vasomotion in the cerebral basilar artery （BA） of Wistar rats. Pressure myograph video microscopy was used to study the changes in cerebral artery vessel diameter. The main results of this study were as follows： （1） The diameters of BA and middle cerebral artery （MCA） were 314.5±15.7 μm （n=15） and 233.3±10.1 μm （n=12） at 10 mmHg working pressure （P〈0.05）, respectively. Pressure-induced vasomotion occurred in BA （22/28, 78.6%）, but not in MCA （4/31, 12.9%） from 0 to 70 mmHg working pressure. As is typical for vasomotion, the contractile phase of the response was more rapid than the relaxation phase; （2） The frequency of vasomotion response and the diameter were gradually increased in BA from 0 to 70 mmHg working pressure. The amplitude of the rhythmic con- tractions was relatively constant once stable conditions were achieved. The frequency of contractions was variable and the highest value was 16.7±4.7 （n=13） per 10 min at 60 mmHg working pressure; （3） The pressure-induced vasomotion of the isolated BA was attenuated by nifedipine, NFA, 181]-GA, TEA or in Ca2＋-free medium. Nifedipine, NFA, 18^-GA or Ca2＋-free medium not only dampened vasomotion, but also kept BA in relaxation state. In contrasts, TEA kept BA in contraction state. These results sug- gest that the pressure-induced vasomotion of the isolated BA results from an interaction between Ca2＋-activated C1- channels （CaCCs） currents and Kca currents. We hypothesize that vasomotion of BA depends on the depolarizing of the vascular smooth muscle cells （VSMCs） to activate CaCCs. Depolarization in turn activates voltage-dependent Ca2＋ channels, synchronizing contractions of adjacent cells through influx of extracellular calcium and the flow of calcium through gap junctions. Subsequent calcium-induced calcium release from ryanodine-sensitive stores activates Kca channels and hyperpo- larizes VSMCs, which provides a negative feedback loop for regenerating the contractile cycle.展开更多
BACKGROUND Heart failure with preserved ejection fraction(HFpEF)accounts for approximately half of heart failure cases and is associated with high morbidity and mortality.Beta-blockers(BB)and calcium channel blockers(...BACKGROUND Heart failure with preserved ejection fraction(HFpEF)accounts for approximately half of heart failure cases and is associated with high morbidity and mortality.Beta-blockers(BB)and calcium channel blockers(CCB)are commonly used for symptom control and comorbidity management,but their comparative effectiveness and safety remain unclear.AIM To compare the effectiveness and safety of BB vs CCB in patients with HFpEF using simulated real-world data and propensity score-matched analyses.METHODS Simulated data for 4000 HFpEF patients(2000 BB,2000 CCB)were generated based on distributions extracted from electronic medical records spanning 2014-2023.Inclusion criteria included adults with left ventricular ejection fraction≥50%and initiation of BB or CCB.Effectiveness outcomes encompassed mortality,heart failure hospitalizations,and changes in clinical parameters.Safety outcomes included bradycardia,hypotension,and drug discontinuation.Statistical analyses used t-tests,χ2 tests,Cox proportional hazards models for hazard ratios(HR),and incidence rate ratios(IRR)in R software.Propensity score matching(PSM)was performed to balance baseline characteristics,with outcomes reassessed in the matched cohort.RESULTS Baseline characteristics were largely balanced,with minor differences in sex,chronic kidney disease,systolic blood pressure,and left atrial volume index.BB demonstrated lower all-cause mortality(crude HR 0.78,95%CI:0.70-0.87,P=0.003),heart failure hospitalization(crude HR 0.86,95%CI:0.77-0.96,P=0.031),and composite endpoint(crude HR 0.85,95%CI:0.79-0.91,P<0.001)rates compared to CCB.IRR for heart failure hospitalizations and emergency visits favored BB.Safety profiles showed higher symptomatic bradycardia(9.2%vs 4.9%,P<0.001)and drug discontinuation(11.3%vs 9.3%,P=0.043)with BB,and higher hypotension(7.2%vs 11.5%,P<0.001)with CCB.Matched analyses showed all-cause mortality rates of 0.0622 per person-year for BB vs 0.0649 for CCB(HR 0.96,95%CI:0.85-1.08),heart failure hospitalization rates of 0.0751 vs 0.0888(HR 0.84,95%CI:0.75-0.94),and IRR for number of heart failure hospitalizations of 1.65 for CCB vs BB(95%CI:1.51-1.80,P<0.001).CONCLUSION BB may offer potential advantages in reducing mortality and hospitalizations in HFpEF compared to CCB,with distinct safety considerations.PSM confirmed these trends with reduced confounding.Personalized therapy is recommended,warranting prospective trials for validation.展开更多
基金Supported by The Natural Science Foundation of China,No.81271950,to Ji QMProjects of International/HMT(Hong Kong,Macao,and Taiwan)Cooperation and Innovation Platform in Science and Technology of Guangdong Higher Education Institutions,No.2012gjhz0009,to Liu ZG+2 种基金Key Laboratory Construction Program of Shenzhen,No.SW201110010,to Liu ZGBasic Research Program of Shenzhen University,No.201101,to Liu ZGBasic Research Foundation of Shenzhen,No.JC201005250059A,JCYJ20120613115535998
文摘AIM: To investigate the effect of polydatin (PD), a resveratrol glucoside, on mast cell degranulation and antiallergic activity. METHODS: After the rats were orally sensitized with ovalbumin (OVA) for 48 d and underwent PD treatment for 4 d, all the rats were stimulated by 100 mg/mL OVA for24 h and then sacrificed for the following experiments. The small intestines from all the groups were prepared for morphology examination by hematoxylin and eosin staining. We also used a smooth muscle organ bath to evaluate the motility of the small intestines. The OVA-specific immunoglobulin E (IgE) production and interleu-kin-4 (IL-4) levels in serum or supernatant of intestinal mucosa homogenates were analyzed by enzyme-linked immunosorbent assay (ELISA). Using toluidine blue stain, the activation and degranulation of isolated rat peritoneal mast cells (RPMCs) were analyzed. Release of histamine from RPMCs was measured by ELISA, and regulation of PD on intracellular Ca 2+ mobilization was investigated by probing intracellular Ca 2+ with fluo-4 fluo-rescent dye, with the signal recorded and analyzed. RESULTS: We found that intragastric treatment with PD significantly reduced loss of mucosal barrier integrity in the small intestine. However, OVA-sensitization caused significant hyperactivity in the small intestine of allergic rats, which was attenuated by PD administration by 42% (1.26 ± 0.13 g vs OVA 2.18 ± 0.21 g, P < 0.01). PD therapy also inhibited IgE production (3.95 ± 0.53 ng/mL vs OVA 4.53 ± 0.52 ng/mL, P < 0.05) by suppressing the secretion of Th2-type cytokine, IL-4, by 34% (38.58 ± 4.41 pg/mLvs OVA 58.15 ± 6.24 pg/mL, P < 0.01). The ratio of degranulated mast cells, as indicated by vehicles (at least five) around the cells, dramatically increased in the OVA group by 5.5 fold (63.50% ± 15.51% vs phosphate-buffered saline 11.15% ± 8.26%, P < 0.001) and fell by 65% after PD treatment (21.95% ± 4.37% vs OVA 63.50% ± 15.51%, P < 0.001). PD mediated attenuation of mast cell degranulation was further confirmed by decreased histamine levels in both serum (5.98 ± 0.17 vs OVA 6.67 ± 0.12, P < 0.05) and intestinal mucosa homogenates (5.83 ± 0.91 vs OVA 7.35 ± 0.97, P < 0.05). Furthermore, we demonstrated that administration with PD significantly decreased mast cell degranulation due to reduced Ca 2+ influx through store-operated calcium channels (SOCs) (2.35 ± 0.39vs OVA 3.51 ± 0.38,P < 0.01).CONCLUSION: Taken together, our data indicate that PD stabilizes mast cells by suppressing intracellular Ca 2+ mobilization, mainly through inhibiting Ca 2+ entry via SOCs, thus exerting a protective role against OVA-sensitized food allergy.
基金supported by the National Natural Science Foundation of China,Nos.81901098(to TC),82201668(to HL)Fujian Provincial Health Technology Project,No.2021QNA072(to HL)。
文摘The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channelspecific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood–brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems.
基金Supported by The National Natural Science Foundation ofChina,No.30670744and81071996Tsinghua-Yue-Yuen Medical Science Foundation,No.20240000531and20240000547
文摘AIM:To further investigate the important role of store-operated calcium channels(SOCs)in rat hepatocytes and to explore the effects of SOC blockers on hepatic ischemia-reperfusion injury(HIRI).METHODS:Using freshly isolated hepatocytes from a rat model of HIRI(and controls),we measured cyto-solic free Ca 2+concentration(by calcium imaging),net Ca 2+fluxes(by a non-invasive micro-test technique),the SOC current(I SOC;by whole-cell patch-clamp record-ing),and taurocholate secretion[by high-performance liquid chromatography and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays].RESULTS:Ca 2+oscillations and net Ca 2+fluxes medi-ated by Ca 2+entry via SOCs were observed in rat he-patocytes.I SOC was significantly higher in HIRI groups than in controls(57.0±7.5 pA vs 31.6±2.7 pA,P<0.05)and was inhibited by La 3+.Taurocholate secretion by hepatocytes into culture supernatant was distinctly lower in HIRI hepatocytes than in controls,an effect reversed by SOC blockers.CONCLUSION:SOCs are pivotal in HIRI.SOC blockers protected against HIRI and assisted the recovery of se-cretory function in hepatocytes.Thus,they are likely to become a novel class of effective drugs for prevention or therapy of HIRI patients in the future.
基金Supported by Calygene Biotechnology Inc.,No.XT[2016]008@。
文摘Type 2 diabetes mellitus(T2DM)is a prevalent metabolic disorder.Despite the availability of numerous pharmacotherapies,a range of adverse reactions,including hypoglycemia,gastrointestinal discomfort,and lactic acidosis,limits their patient applicability and long-term application.Therefore,it is necessary to screen novel therapeutic drugs for T2DM treatment that have high efficacy but few adverse effects.AMP-activated protein kinase(AMPK)stands out as one of the most powerful targets for T2DM treatment.It can be activated through energysensing or calcium signaling.Medications that activate AMPK through the energy-sensing mechanism exhibit remarkable potency,but they are accompanied by lactic acidosis,carrying an alarmingly high mortality rate.Interestingly,medications that activate AMPK through calcium signaling,such as gliclazide,seldom induce lactic acidosis.However,the efficacy of gliclazide is much lower than metformin.Therefore,it is necessary to explore targets that activate AMPK via calcium signaling to avoid lactic acidosis while maintaining high potency.Ion channels are the main controller of intracellular calcium flow.Specific agonists and inhibitors targeting ion channels have been reported to activate AMPK.In this review,we will summarize the structure and function of calcium-permeable ion channels and discuss the potential of targeting these calcium channels for T2DM treatment.
文摘Aim: To study the effects of rhynchophylline (Rhy) on the L type calcium channels in freshly dissociated cortical neurons of Wistar rats during acute hypoxia. Methods: Cell attached configuration of patch clamp technique. L type calcium channel was activated by stepping from 40 mV to 0 mV. Results: The results showed that the L type calcium channels of cortical neurons were activated by acute hypoxia. The mean open time of the channel was increased, the mean close time decreased and the open state probability raised during acute hypoxia. Rhy (15 and 30μmol·L -1 ) in concentration dependent manner blocked activity of the channels. The drug shortened the mean open time of the channels from 8 87 ms to 3 03 ms and 2 23 ms ( P 【0 001), prolonged the mean close time from 9 23 ms to 38 84 ms and 54 43 ms ( P 【0 001), and decreased the open state probability from 0 142 to 0 031 and 0 025 ( P 【0 001) under the hypoxia condition, respectively. The effects of Rhy were similar to but weaker than those of verapamil (15 μmol·L -1 ). Conclusion: The study confirmed that Rhy has the blockade effects on L type calcium channels in cortical neurons of rats during hypoxia, by which it protects the brain from hypoxic injury.
文摘Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear; however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers.
基金Supported by National Natural Science Foundation of China,No.31171107,No.31071011 and No.31271236
文摘AIM:To investigate the effect of hydrogen sulfide(H2S)on smooth muscle motility in the gastric fundus.METHODS:The expression of cystathionineβ-synthase(CBS)and cystathionineγ-lyase(CSE)in cultured smooth muscle cells from the gastric fundus was examined by the immunocytochemistry technique.The tension of the gastric fundus smooth muscle was recorded by an isometric force transducer under the condition of isometric contraction with each end of the smooth muscle strip tied with a silk thread.Intracellular recording was used to identify whether hydrogen sulfide affects the resting membrane potential of the gastric fundus in vitro.Cells were freshly separated from the gastric fundus of mice using a variety of enzyme digestion methods and whole-cell patch-clamp technique was used to find the effects of hydrogen sulfide on voltage-dependent potassium channel and calcium channel.Calcium imaging with fura-3AM loading was used to investigate the mechanism by which hydrogen sulfide regulates gastric fundus motility in cultured smooth muscle cells.RESULTS:We found that both CBS and CSE were expressed in the cul tured smooth muscle cel ls from the gastric fundus and that H2S increased the smooth muscle tension of the gastric fundus in mice at low concentrations.In addition,nicardipine and aminooxyacetic acid(AOAA),a CBS inhibitor,reduced the tension,whereas Nω-nitro-L-arginine methyl ester,a nonspecific nitric oxide synthase,increased the tension.The AOAA-induced relaxation was significantly recovered by H2S,and the Na HS-induced increase in tonic contraction was blocked by 5 mmol/L4-aminopyridine and 1μmol/L nicardipine.Na HS significantly depolarized the membrane potential and inhibited the voltage-dependent potassium currents.Moreover,Na HS increased L-type Ca2+currents and caused an elevation in intracellular calcium([Ca2+]i).CONCLUSION:These findings suggest that H2S may be an excitatory modulator in the gastric fundus in mice.The excitatory effect is mediated by voltagedependent potassium and L-type calcium channels.
基金supported by grants from the National Natural Science Foundation of China (81171042,81070893 and 81221002)the Beijing Outstanding Ph.D.Program Mentor Grantthe Specialized Research Fund for Doctoral Programs of Higher Education, China(20110001110058)
文摘Objective Formaldehyde at high concentrations is a contributor to air pollution. It is also an endogenous metabolic product in cells, and when beyond physiological concentrations, has pathological effects on neurons. Formaldehyde induces mis-folding and aggregation of neuronal tau protein, hippocampal neuronal apoptosis, cognitive impairment and loss of memory functions, as well as excitation of peripheral nociceptive neurons in cancer pain models. Intracellular calcium （[Ca2＋]i） is an important intracellular messenger, and plays a key role in many pathological processes. The present study aimed to investigate the effect of formaldehyde on [Ca2＋]i and the possible involvement of N-methyl-D-aspartate receptors （NMDARs） and T-type Ca2＋ channels on the cell membrane. Methods Using primary cultured hippocampal neurons as a model, changes of [Ca2＋]i in the presence of formaldehyde at a low concentration were detected by confocal laser scanning microscopy. Results Formaldehyde at 1 mmol/L approximately doubled [Ca2＋]i. （2R）-amino-5-phosphonopentanoate （AP5, 25 μmol/L, an NMDAR antagonist） and mibefradil （MIB, 1 μmol/L, a T-type Ca2＋ channel blocker）, given 5 min after formaldehyde perfusion, each partly inhibited the formaldehyde-induced increase of [Ca：＋]i, and this inhibitory effect was reinforced by combined application of AP5 and MIB. When applied 3 min before formaldehyde perfusion, AP5 （even at 50μmol/L） did not inhibit the formaldehyde-induced increase of [Ca2＋]i, but MIB （1 μmol/L） significantly inhibited this increase by 70%. Conclusion These results suggest that formaldehyde at a low concentration increases [Ca2＋]i in cultured hippocampal neurons; NMDARs and T-type Ca2＋ channels may be involved in this process.
基金the National Natural Science Foundation of China,No.30270532 Trans-Century Training Programme Foundation for the Talents by the Ministry of Education of China, No. 2002-48Shuguang Program Project of Shanghai Educational Committee,No.02SG20
文摘AIM： To study the effects of hepatic ischemia/ reperfusion （I/R） injury on store-operated calcium channel （SOC） currents （Isoc） in freshly isolated rat Kupffer cells, and the effects of Ca^2＋ channel blockers, 2-aminoethoxydiphenyl borate （2-APB）, SK＆F96365, econazole and miconazole, on Isoc in isolated rat Kupffer cells after hepatic I/R injury.METHODS： The model of rat hepatic I/R injury was established. Whole-cell patch-clamp techniques were performed to investigate the effects of 2-APB, SK＆F96365, econazole and miconazole on Isoc in isolated rat Kupffer cells after hepatic I/R injury.RESULTS： I/R injury significantly increased Isoc from -80.4±25.2pA to -159.5±34.5pA （^bp 〈 0.01, n = 30）. 2-APB （20, 40, 60, 80, 100 pmol/L）, SK＆F96365 （5, 10, 20, 40, 50 pmol/L）, econazole （0.1, 0.3, 1, 3, 10 μmol/L） and miconazole （0.1, 0.3, 1, 3, 10 μmol/L） inhibited Isoc in a concentration-dependent manner with IC50 of 37.41 μmol/L （n = 8）, 5.89 μmol/L （n = 11）, 0.21 μmol/L （n = 13）, and 0.28 μmol/L （n = 10）. The peak value of Isoc in the I-V relationship was decreased by the blockers in different concentrations, but the reverse potential of Isoc was not transformed. CONCLUSION： SOC is the main channel for the influx of Ca^2＋ during hepatic I/R injuries. Calcium channel blockers, 2-APB, SK＆F96365, econazole and miconazole,have obviously protective effects on I/R injury, probably by inhibiting Isoc in Kupffer cells and preventing the activation of Kupffer cells.
基金supported by an Alzheimer’s Research Trust(UK)Programme Grant(ART/PG2004A/1)to A.V.by a National Science Foundation grant(CBET 0943343)to V.P
文摘Neuroglial cells are homeostatic neural cells. Generally, they are electrically non-excitable and their activation is associated with the generation of complex intracellular Ca^2＋ signals that define the ＂Ca^2＋ excitability＂ of glia. In mammalian glial cells the major source of Ca^2＋ for this excitability is the lumen of the endoplasmic reticulum （ER）, which is ultimately （re）filled from the extracellular space. This occurs via store-operated Ca^2＋ entry （SOCE） which is supported by a specific signaling system connecting the ER with plasmalemmal Ca^2＋ entry. Here, emptying of the ER Ca^2＋ store is necessary and sufficient for the activation of SOCE, and without Ca^2＋ influx via SOCE the ER store cannot be refilled. The molecular arrangements underlying SOCE are relatively complex and include plasmalemmal channels, ER Ca^2＋ sensors, such as stromal interaction molecule, and possibly ER Ca^2＋ pumps （of the SERCA type）. There are at least two sets of plasmalemmal channels mediating SOCE, the Ca2＊-release activated channels, Orai, and transient receptor potential （TRP） channels. The molecular identity of neuroglial SOCE has not been yet identified unequivocally. However, it seems that Orai is predominantly expressed in microglia, whereas astrocytes and oligodendrocytes rely more on TRP channels to produce SOCE. In physiological conditions the SOCE pathway is instrumental for the sustained phase of the Ca^2＋ signal observed following stimulation of metabotropic receptors on glial cells.
基金Supported by Thailand Research Fund grants RTA5280006 (Chattipakorn N)BRG5480003(Chattipakorn S)+1 种基金the National Research Council of Thailand(Chattipakorn N)the Thai-land Research Fund Royal Golden Jubilee project(Kumfu S and Chattipakorn N)
文摘Iron overload can lead to iron deposits in many tissues,particularly in the heart.It has also been shown to be associated with elevated oxidative stress in tissues.Elevated cardiac iron deposits can lead to iron overload cardiomyopathy,a condition which provokes mortality due to heart failure in iron-overloaded patients.Currently,the mechanism of iron uptake into cardiomyocytes is still not clearly understood.Growing evidence suggests L-type Ca2+channels(LTCCs)as a possible pathway for ferrous iron(Fe2+)uptake into cardiomyocytes under iron overload conditions.Nevertheless,controversy still exists since some findings on pharmacological interventions and those using different cell types do not support LTCC’s role as a portal for iron uptake in cardiac cells.Recently,T-type Ca2+channels (TTCC)have been shown to play an important role in the diseased heart.Although TTCC and iron uptake in cardiomyocytes has not been investigated greatly,a recent finding indicated that TTCC could be an important portal in thalassemic hearts.In this review,comprehensive findings collected from previous studies as well as a discussion of the controversy regarding iron uptake mechanisms into cardiomyocytes via calcium channels are presented with the hope that understanding the cellular iron uptake mechanism in cardiomyocytes will lead to improved treatment and prevention strategies,particularly in iron-overloaded patients.
基金supported by the National Natural Science Foundation,Beijing,People’s Republic of China(81671058 and 81730031 to YW and 81401089 to MD)the National Research Foundation of Korea grants funded by the Republic of Korea(2019R1I1A1A01057744 to YK)the Foundation of Shanghai Municipal Science and Technology Commission(19ZR1407500 to FS)。
文摘In the current study,we sought to investigate whether T-type Ca^(2+)channels(TCCs)in the brain are involved in generating post-anesthetic hyperexcitatory behaviors(PAHBs).We found that younger rat pups(postnatal days 9-11)had a higher incidence of PAHBs and higher PAHB scores than older pups(postnatal days16-18)during emergence from sevoflurane anesthesia.The power spectrum of the theta oscillations(4 Hz-8 Hz)in the prefrontal cortex was significantly enhanced in younger pups when PAHBs occurred,while there were no significant changes in older pups.Both the power of theta oscillations and the level of PAHBs were significantly reduced by the administration of TCC inhibitors.Moreover,the sensitivity of TCCs in the medial dorsal thalamic nucleus to sevoflurane was found to increase with age by investigating the kinetic properties of TCCs in vitro.TCCs were activated by potentiated GABAergic depolarization with a sub-anesthetic dose of sevoflurane(1%).These data suggest that(1)TCCs in the brain contribute to the generation of PAHBs and the concomitant electroencephalographic changes;(2)the stronger inhibitory effect of sevoflurane contributes to the lack of PAHBs in older rats;and(3)the contribution of TCCs to PAHBs is not mediated by a direct effect of sevoflurane on TCCs.
基金National Natural Science Foundation of China (81201057)Shanghai Municipal Health Bureau Project (20124109)+1 种基金Chinese Medical Association, Psychiatry-Servier Youth Research Fund, Shanghai Mental Health Center International Cooperation Project (2013-)Sha叩hai Municipal Center for Mental Health Clinical Research Program.
文摘LTCCS ARE IMPLICATED IN THE PATHOLOGY OF BIPOLAR DISORDER Bipolar disorder (BPD) is a common mental illness with significant morbidity and mortality.1 Although evidence have suggested changes in oxidative stress, dopamine and inflammation in BPD, it is hard to define the aetiological mechanism of BPD clearly. Recently, some but not all candidate gene association studies, family-based association studies, linkage studies, genome-wide association studies (GWASs) and meta-analyses showed that mutation of L-type voltage-gated calcium chan? nels (LTCCs) gene CACNAlCis implicated in the mechanism of BPD.'-8 These findings support the possibility that BPD might have calcium channelopathy.
文摘The acrosome reaction （AR）, an absolute requirement for spermatozoa and egg fusion, requires the influx of Ca2＋ into the spermatozoa through voltage-dependent Ca2＋ channels and store-operated channels. Maitotoxin （MTx）, a Ca2＋-mobilizing agent, has been shown to be a potent inducer of the mouse sperm AR, with a pharmacology similar to that of the zona pellucida （ZP）, possibly suggesting a common pathway for both inducers. Using recombinant human ZP3 （rhZP3）, mouse ZP and two MTx channel blockers （U73122 and U73343）, we investigated and compared the MTx- and ZP-induced ARs in human and mouse spermatozoa. Herein, we report that MTx induced AR and elevated intracellular Ca2＋ （[Ca2＋]~） in human spermatozoa, both of which were blocked by U73122 and U73343. These two compounds also inhibited the MTx-induced AR in mouse spermatozoa. In disagreement with our previous proposal, the AR triggered by rhZP3 or mouse ZP was not blocked by U73343, indicating that in human and mouse spermatozoa, the AR induction by the physiological ligands or by MTx occurred through distinct pathways. U73122, but not U73343 （inactive analogue）, can block phospholipase C （PLC）. Another PLC inhibitor, edelfosine, also blocked the rhZP3- and ZP-induced ARs. These findings confirmed the participation of a PLC-dependent signalling pathway in human and mouse zona protein-induced AR. Notably, edelfosine also inhibited the MTx-induced mouse sperm AR but not that of the human, suggesting that toxin-induced AR is PLC-dependent in mice and PLC-independent in humans.
基金supported by the National Natural Science Foundation of China(32322041,W2412029,32321001,32471279)USTC Research Funds of the Double First-Class Initiative(YD9100002004,YD9100002020)+2 种基金Fundamental Research Funds for the Central Universities(WK9100000031)Research Funds of Center for Advanced Interdisciplinary Science and Biomedicine of IHM(QYPY20230034)the Natural Science Foundation of Anhui Province(2408085JX005).
文摘Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thaliana,the OSCA family has been identified as mechanically activated ion channels that respond to osmotic stress by allowing calcium ions to enter the cell.This influx increases the cytoplasmic calcium concentration,triggering osmotic stress-induced signal transduction cascades in plants.In this study,we determined the structures of OSCA2.2 and OSCA3.1 via cryoelectron microscopy(cryo-EM).Both proteins form homodimers consisting of 11 transmembrane helices(TM1–11).The ion conduction pathway is formed by TM4–8.Despite belonging to the same family,OSCA2.2 and OSCA3.1 exhibit notable structural variations.Structural analysis revealed that both OSCA2.2 and OSCA3.1 exhibit a closed conformation.We also conducted functional studies on OSCA proteins via electrophysiological experiments and confirmed the role of key amino acids in the process of ion permeation.
文摘In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium. Attached cells when stimulated with high potassium secreted large amount of amylase. High potassium-induced secretion was dependent both on the concentration of potassium and duration of stimulation. High potassium induced increases in intracellular calcium were inhibited by voltage-dependent calcium channel antagonists with an order of potency as follows: nifedipine > ω-agatoxin IVA > ω-conotoxin GVIA. In contrast, the L-type calcium channel antagonist nifedipine almost completely inhibited potassium-induced amylase secretion, whereas the N-type channel antagonist ω-conotoxin GVIA was without effect. The P-type channel antagonist ω-agatoxin IVA had a small inhibitory effect, but this inhibition was not significant at the level of amylase secretion. In conclusion, the AR4-2J cell line possesses different voltage-dependent calcium channels (L, P,N) with the L-type predominantly involved in depolarization induced amylase secretion.
基金supported by the CIIT-TWAS Sandwich Postgraduate Fellowship(FR number:3240293217,2016).
文摘Objective:To evaluate spasmolytic mechanisms of aqueous and methanolic extracts from Distemonanthus benthamianus trunk-bark.Methods:Spasmolytic activities of extracts were evaluated in vitro on spontaneous and potassium chloride-induced jejunum contractions,or against cholinergic[acetylcholine(0.3μmol/L)]stimulations.High performance liquid chromatography analysis of both extracts was performed in reference to standard compounds.Results:Extracts developed concentration-dependent inhibitory activities.The methanolic extract,which revealed better activity,produced spasmolytic and myorelaxant effects at concentrations of 0.01-0.30 mg/mL with EC(50)of 0.06 and 0.09 mg/mL(95%CI:0.03-0.3 mg/mL),respectively.Its anticholinergic effect was obtained at the same concentrations with EC(50)of 0.11 mg/mL(95%CI:0.03-0.3 mg/mL).Chromatograms showed the presence of gallic acid in both extracts,rutin being only detected in the aqueous extract.Conclusions:Distemonanthus benthamianus extracts exhibit verapamil and atropine-like activities,thus highlighting calcium channels and muscarinic receptors blocking potentials,which may be conveyed by some phenolic compounds.These results confirm the antidiarrheal activity of Distemonanthus benthamianus extracts.
基金This project was supported by the National Natural Sci ence Foundation of China (No. 30270532), the Trans Cen tury Excellent Talent Development Plan Fund of Ministry ofEducation of China (Official Letter No. 2002 48) and Shu guang Program Project of Shanghai Educational Committee(No. 02SG20).
文摘The effects of hepatic ischemia/reperfusion (I/R) injuries on hepatocellular viability and store-operated calcium current (Isoc) in isolated rat hepatocytes and the effects of 2-APB on store-operated calcium current (Isoc) in isolated rat hepatocytes after hepatic ischemia/reperfusion injuries were studied. Hepatic ischemia and reperfusion injury model was established and whole cell patch-clamp techniques were used to investigate the effects of 2-APB on Isoc. The results showed that ischemia/reperfusion injuries could significantly reduce hepatocellular viability and further increase Isoc in hepatocytes and 2-APB (20, 40, 60, 80, 100 μmol/L) produced a concentration-dependent decrease of Isoc with IC 50 value of 64.63±10.56 μmol/L (n=8). It was concluded that ischemia/reperfusion injuries could reduce hepatocellular viability, probably through increased Isoc in hepatocytes and 2-APB had a protective effect on ischemia/reperfusion-induced liver injury, probably though inhibiting Isoc.
基金supported by grants from National Basic Research Program of China(No.2012CB52660000)National Natural Science Foundation of China(No.81000411,No.31100829,and No.31260247)
文摘Spontaneous, rhythmical contractions, or vasomotion, can be recorded from cerebral vessels under both normal physiological and pathophysiological conditions. We investigated the cellular mechanisms underlying vasomotion in the cerebral basilar artery （BA） of Wistar rats. Pressure myograph video microscopy was used to study the changes in cerebral artery vessel diameter. The main results of this study were as follows： （1） The diameters of BA and middle cerebral artery （MCA） were 314.5±15.7 μm （n=15） and 233.3±10.1 μm （n=12） at 10 mmHg working pressure （P〈0.05）, respectively. Pressure-induced vasomotion occurred in BA （22/28, 78.6%）, but not in MCA （4/31, 12.9%） from 0 to 70 mmHg working pressure. As is typical for vasomotion, the contractile phase of the response was more rapid than the relaxation phase; （2） The frequency of vasomotion response and the diameter were gradually increased in BA from 0 to 70 mmHg working pressure. The amplitude of the rhythmic con- tractions was relatively constant once stable conditions were achieved. The frequency of contractions was variable and the highest value was 16.7±4.7 （n=13） per 10 min at 60 mmHg working pressure; （3） The pressure-induced vasomotion of the isolated BA was attenuated by nifedipine, NFA, 181]-GA, TEA or in Ca2＋-free medium. Nifedipine, NFA, 18^-GA or Ca2＋-free medium not only dampened vasomotion, but also kept BA in relaxation state. In contrasts, TEA kept BA in contraction state. These results sug- gest that the pressure-induced vasomotion of the isolated BA results from an interaction between Ca2＋-activated C1- channels （CaCCs） currents and Kca currents. We hypothesize that vasomotion of BA depends on the depolarizing of the vascular smooth muscle cells （VSMCs） to activate CaCCs. Depolarization in turn activates voltage-dependent Ca2＋ channels, synchronizing contractions of adjacent cells through influx of extracellular calcium and the flow of calcium through gap junctions. Subsequent calcium-induced calcium release from ryanodine-sensitive stores activates Kca channels and hyperpo- larizes VSMCs, which provides a negative feedback loop for regenerating the contractile cycle.
文摘BACKGROUND Heart failure with preserved ejection fraction(HFpEF)accounts for approximately half of heart failure cases and is associated with high morbidity and mortality.Beta-blockers(BB)and calcium channel blockers(CCB)are commonly used for symptom control and comorbidity management,but their comparative effectiveness and safety remain unclear.AIM To compare the effectiveness and safety of BB vs CCB in patients with HFpEF using simulated real-world data and propensity score-matched analyses.METHODS Simulated data for 4000 HFpEF patients(2000 BB,2000 CCB)were generated based on distributions extracted from electronic medical records spanning 2014-2023.Inclusion criteria included adults with left ventricular ejection fraction≥50%and initiation of BB or CCB.Effectiveness outcomes encompassed mortality,heart failure hospitalizations,and changes in clinical parameters.Safety outcomes included bradycardia,hypotension,and drug discontinuation.Statistical analyses used t-tests,χ2 tests,Cox proportional hazards models for hazard ratios(HR),and incidence rate ratios(IRR)in R software.Propensity score matching(PSM)was performed to balance baseline characteristics,with outcomes reassessed in the matched cohort.RESULTS Baseline characteristics were largely balanced,with minor differences in sex,chronic kidney disease,systolic blood pressure,and left atrial volume index.BB demonstrated lower all-cause mortality(crude HR 0.78,95%CI:0.70-0.87,P=0.003),heart failure hospitalization(crude HR 0.86,95%CI:0.77-0.96,P=0.031),and composite endpoint(crude HR 0.85,95%CI:0.79-0.91,P<0.001)rates compared to CCB.IRR for heart failure hospitalizations and emergency visits favored BB.Safety profiles showed higher symptomatic bradycardia(9.2%vs 4.9%,P<0.001)and drug discontinuation(11.3%vs 9.3%,P=0.043)with BB,and higher hypotension(7.2%vs 11.5%,P<0.001)with CCB.Matched analyses showed all-cause mortality rates of 0.0622 per person-year for BB vs 0.0649 for CCB(HR 0.96,95%CI:0.85-1.08),heart failure hospitalization rates of 0.0751 vs 0.0888(HR 0.84,95%CI:0.75-0.94),and IRR for number of heart failure hospitalizations of 1.65 for CCB vs BB(95%CI:1.51-1.80,P<0.001).CONCLUSION BB may offer potential advantages in reducing mortality and hospitalizations in HFpEF compared to CCB,with distinct safety considerations.PSM confirmed these trends with reduced confounding.Personalized therapy is recommended,warranting prospective trials for validation.
