Dopaminergic neurons in the ventral tegmental area(VTA)play an important role in cognition,emergence from anesthesia,reward,and aversion,and their projection to the cortex is a crucial part of the"bottom-up"...Dopaminergic neurons in the ventral tegmental area(VTA)play an important role in cognition,emergence from anesthesia,reward,and aversion,and their projection to the cortex is a crucial part of the"bottom-up"ascending activating system.The prelimbic cortex(PrL)is one of the important projection regions of the VTA.However,the roles of dopaminergic neurons in the VTA and the VTADA–PrL pathway under sevoflurane anesthesia in rats remain unclear.In this study,we found that intraperitoneal injection and local microinjection of a dopamine D1 receptor agonist(Chloro-APB)into the PrL had an emergence-promoting effect on sevoflurane anesthesia in rats,while injection of a dopamine D1 receptor antagonist(SCH23390)deepened anesthesia.The results of chemogenetics combined with microinjection and optogenetics showed that activating the VTADA–PrL pathway prolonged the induction time and shortened the emergence time of anesthesia.These results demonstrate that the dopaminergic system in the VTA has an emergence-promoting effect and that the bottom-up VTADA–PrL pathway facilitates emergence from sevoflurane anesthesia.展开更多
Objective: To investigate the effect of crocin carotenoid on BNDF and CREB gene expression in the brain ventral tegmental area(VTA) and the serum level of BDNF in morphine-treated rats compared to control. Methods: In...Objective: To investigate the effect of crocin carotenoid on BNDF and CREB gene expression in the brain ventral tegmental area(VTA) and the serum level of BDNF in morphine-treated rats compared to control. Methods: In this study, 40 male Wistar rats(200-250 g) were used in 5 experimental groups: 1) non morphine treat rats(control); 2) non morphine-treated rats with 25 mg/kg crocin carotenoid(i.p., for 21 d); 3) morphine treated rats(10 mg/kg twice a day, s.c., 21 d); 4 and 5) morphine-treated rats with 12.5 and 25 mg/kg crocin carotenoid, respectively. By the end of research, BDNF and CREB expression was determined by real-time-PCR method. ELISA analysis was also applied for assessing the serum BDNF level. Results: The data indicated that morphine treatment could cause a significant decrease in BDNF and CREB gene expression(P<0.01 and P<0.001, respectively) in brain VTA as well as serum level of BDNF(P<0.01) in comparison to control group. Treatment with 25 mg/kg crocin carotenoid caused a significant enhancement in BDNF and CREF gene expression(P<0.01 and P<0.05, respectively) and serum level of BDNF(P<0.01) in morphine-treated rats in comparison to morphine-treated group. Conclusions: Regarding to obtained results, crocin carotenoid can inhibit unfavorable effects of morphine on the neural system to some extent through enhancing BDNF and CREB gene expression in brain VTA and serum level of BDNF.展开更多
Neurons in the laterodorsal tegmentum (LDTg) and pedunculopontine tegmental nucleus (PPTg) play important roles in central autonomic circuits of the kidney. In this study, we used a combination of retrograde tracers p...Neurons in the laterodorsal tegmentum (LDTg) and pedunculopontine tegmental nucleus (PPTg) play important roles in central autonomic circuits of the kidney. In this study, we used a combination of retrograde tracers pseudorabies virus (PRV)-614 and fluorescence immunohistochemistry to characterize the neuroanatomic substrate of PPTg and LDTg innervating the kidney in the mouse. PRV-614-infected neurons were retrogradely labeled in the rostral and middle parts of LDTg, and the middle and caudal parts of PPTg after tracer injection in the kidney. PRV-614/TPH double-labeled neurons were mainly localized in the rostral of LDTg, whereas PRV-614/TH neurons were scattered within the three parts of LDTg. PRV-614/TPH and PRV-614/TH neurons were located predominantly in the caudal of PPTg (cPPTg). These data provided direct neuroanatomical foundation for the identification of serotonergic and catecholaminergic projections from the mid-brain tegmentum to the kidney.展开更多
Prior work has shown that systemic cocaine pretreatment augments cocaine conditioned place preference (CPP) in rats. In contrast, ghrelin receptor antagonism attenuates cocaine and amphetamine-induced CPP. In order to...Prior work has shown that systemic cocaine pretreatment augments cocaine conditioned place preference (CPP) in rats. In contrast, ghrelin receptor antagonism attenuates cocaine and amphetamine-induced CPP. In order to further investigate ghrelin’s role in dopamine-mediated reward, the present report examined whether pretreament with ghrelin, administered directly into the ventral tegmental area (VTA) of the midbrain, would potentiate the rewarding properties of cocaine as measured by CPP. Adult male Sprague-Dawley rats were given access to either side of the CPP chamber in order to determine initial side preferences. The rats were then restricted to either their non-preferred or preferred side over the course of conditioning which lasted for a total of 16 consecutive days. This was followed by a final test day to then reassess preference. On days where rats were confined to their non-preferred side, ghrelin (30-300 pmol) and cocaine (0.625-10 mg/kg IP) were administered immediately prior to the conditioning trial. On alternate days rats were treated with vehicle and placed into what was initially determined to be their preferred side. CPP was calculated as the difference in percentage of total time spent in the treatment-paired compartment during the post-conditioning session and the pre-conditioning session. Our results indicated that both cocaine and ghrelin elicited CPP and that ghrelin pretreatment potentiated the effect of cocaine on place preference. Overall, these findings provide additional support for the argument that ghrelin signaling within the VTA enhances the rewarding effects of psychostimulant compounds.展开更多
Nicotine is widely recognized as the primary contributor to tobacco dependence.Previous studies have indicated that molecular and behavioral responses to nicotine are primarily mediated by ventral tegmental area(VTA)n...Nicotine is widely recognized as the primary contributor to tobacco dependence.Previous studies have indicated that molecular and behavioral responses to nicotine are primarily mediated by ventral tegmental area(VTA)neurons,and accumulating evidence suggests that glia play prominent roles in nicotine addiction.However,VTA neurons and glia have yet to be characterized at the transcriptional level during the progression of nicotine self-administration.Here,a male mouse model of nicotine self-administration is established and the timing of three critical phases(pre-addiction,addicting,and post-addiction phase)is characterized.Single-nucleus RNA sequencing in the VTA at each phase is performed to comprehensively classify specific cell subtypes.Adaptive changes occurred during the addicting and post-addiction phases,with the addicting phase displaying highly dynamic neuroplasticity that profoundly impacts the transcription in each cell subtype.Furthermore,significant transcriptional changes in energy metabolism-related genes are observed,accompanied by notable structural alterations in neuronal mitochondria during the progression of nicotine self-administration.The results provide insights into mechanisms underlying the progression of nicotine addiction,serving as an important resource for identifying potential molecular targets for nicotine cessation.展开更多
Rapid eye movement(REM)sleep behavior disorder(RBD)is a parasomnia that is featured by elevated motor behaviors and dream enactments during REM sleep.Clinical observations show that RBD bears significant relevance wit...Rapid eye movement(REM)sleep behavior disorder(RBD)is a parasomnia that is featured by elevated motor behaviors and dream enactments during REM sleep.Clinical observations show that RBD bears significant relevance with several synucleinopathies such as Lewy body dementia and Parkinson disease(PD),and often develops prior to their diagnosis.Being a potential biomarker of PD,investigating the relationship of RBD symptoms and their emergence in developing PD would provide insight intoits pathogenesis.Here,in a chronic model of PD,rats with daily rotenone treatment exhibited key RBD features,including elevated sleep muscle tone,sleep fragmentation and EEG slowing at different time points.Based on detectedearly alpha synuclein aggregation and neural apoptosis in the sublaterodorsal tegmental nucleus(SLD),an area known to promote REM sleep and maintain sleep muscle atonia,the possible involvement of SLD glutamatergic neurons was interrogated.Via chemogenetic activation of SLD glutamatergic neurons,key RBD symptoms and EEG slowing in REM sleep were alleviated.These results are consistent with a progressive degeneration in REM sleep promoting pathways.Our findings provide a foundation for further studies into RBD and its relationship to neurodegenerative diseases.展开更多
Methylphenidate (MPD) is considered as the first-line pharmacotherapy to treat ADHD. More recently, MPD has also been used as a cognitive enhancement recreationally. Its therapeutic effects are not fully understood, n...Methylphenidate (MPD) is considered as the first-line pharmacotherapy to treat ADHD. More recently, MPD has also been used as a cognitive enhancement recreationally. Its therapeutic effects are not fully understood, nor are the long term effects of the drug on brain development. The ventral tegmental area (VTA) neuronal activity was recorded from freely behaving adolescent rats using a wireless recording system. Five groups were used: saline, 0.6, 2.5, 5.0 and 10.0 mg/kg MPD. The experiment lasted for 10 days. This study demonstrated that VTA neurons respond to MPD in a dose response characteristic and the same dose of MPD can cause both behavioral sensitization and behavioral tolerance. The neuronal unit activity was evaluated based on the animals’ behavioral activity following chronic MPD administration. The study showed that the animals’ behavioral response to different acute MPD of 0.6, 2.5 and 10.0 mg/kg doses responded in a dose response characteristics. Moreover, the same chronic dose of 0.6, 2.5, and 10.0 mg/kg MPD elicits in some animals’ behavioral sensitization and in some others behavioral tolerance. Therefore, the neuronal activity recorded from animals expressing behavioral sensitization was analyzed separately from the neuronal activity recorded from of behaviorally tolerant animals and it was found that the VTA units of the behaviorally sensitization animals responded significantly different to the drug than those VTA units recorded from animals expressing behavioral tolerance.展开更多
The mesolimbic dopamine system consisting of dopaminergic neurons projecting from the ventral tegmental area (VTA) to the nucleus accumbens (N.Acc.) mediates the reinforcing effects of addictive drugs including alcoho...The mesolimbic dopamine system consisting of dopaminergic neurons projecting from the ventral tegmental area (VTA) to the nucleus accumbens (N.Acc.) mediates the reinforcing effects of addictive drugs including alcohol. Given that VTA is a heterogeneous area and that alcohol, in rather low doses, interacts directly with ligand-gated ion channels, we hypothesised that low, rather than high, doses of alcohol into the VTA activate the mesolimbic dopamine system and that alcohol may have different effects in the anterior and posterior parts of the VTA. The present study was undertaken to investigate this hypothesis. The present series of experiment show that infusion of a low dose of alcohol (20 mM) into the anterior, but not posterior, part of the VTA increases accumbal dopamine release in rats. In addition, higher doses of alcohol (100 or 300 mM) into the anterior or posterior part of the VTA do not affect the release of dopamine in the N.Acc., suggesting that low doses of alcohol can activate the mesolimbic dopamine system via mechanisms in the VTA. These data contribute to understanding the neuronal mechanisms underlying the dependence-producing properties of alcohol and could tentatively contribute to that new treatment strategies for alcohol use disorder can be developed.展开更多
Chronic pain often develops severe mood changes such as depression.However,how chronic pain leads to depression remains elusive and the mechanisms determining individuals’responses to depression are largely unexplore...Chronic pain often develops severe mood changes such as depression.However,how chronic pain leads to depression remains elusive and the mechanisms determining individuals’responses to depression are largely unexplored.Here we found that depression-like behaviors could only be observed in 67.9%of mice with chronic neuropathic pain,leaving 32.1%of mice with depression resilience.We determined that the spike discharges of the ventral tegmental area(VTA)-projecting lateral habenula(LHb)glutamatergic(Glu)neurons were sequentially increased in sham,resilient and susceptible mice,which consequently inhibited VTA dopaminergic(DA)neurons through a LHbGlu-VTAGABA-VTADA circuit.Furthermore,the LHbGlu-VTADA excitatory inputs were dampened via GABAB receptors in a pre-synaptic manner.Regulation of LHb-VTA pathway largely affected the development of depressive symptoms caused by chronic pain.Our study thus identifies a pivotal role of the LHb-VTA pathway in coupling chronic pain with depression and highlights the activity-dependent contribution of LHbGlu-to-VTADA inhibition in depressive behavioral regulation.展开更多
Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice ...Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific,particularly involving the corticolimbic system,including the ventral tegmental area,nucleus accumbens,prefrontal cortex,amygdala,and hippocampus.Determining how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress psychopathology.In this review,we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of depression.We focused on associated molecular pathways and neural circuits,with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine circuit.We determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature,severity,and duration of stress,especially in the above-mentioned brain regions of the corticolimbic system.Therefore,BDNF might be a biological indicator regulating stress-related processes in various brain regions.展开更多
Dear Editor,Post-traumatic stress disorder(PTSD)is a chronic neuropsychiatric disorder triggered by severe traumatic events,characterized by persistent intrusive memories,emotional dysregulation,hyperarousal,and avoid...Dear Editor,Post-traumatic stress disorder(PTSD)is a chronic neuropsychiatric disorder triggered by severe traumatic events,characterized by persistent intrusive memories,emotional dysregulation,hyperarousal,and avoidance behaviors[1,2].PTSD is associated with significant gene expression changes in key brain regions,including the ventral tegmental area(VTA),which may underlie dysregulation of dopaminergic signaling and stress-related behaviors[3].展开更多
Social hierarchies are central to the organizational structure of group-living species,shaping individual physiology,behavior,and social interactions.Dopaminergic(DA)systems,particularly within the ventral tegmental a...Social hierarchies are central to the organizational structure of group-living species,shaping individual physiology,behavior,and social interactions.Dopaminergic(DA)systems,particularly within the ventral tegmental area(VTA)and dorsal raphe nucleus(DR),have been linked to motivation and competitive behaviors,yet their region-specific contributions to social dominance remain insufficiently defined.This study investigated the role of VTA and DR DA neurons in regulating social dominance in sexually naïve male C57BL/6J mice.Stable hierarchies were established using the tube test,after which both dominant and subordinate mice exhibited elevated c-Fos expression within the VTA and DR.Notably,dominant mice displayed significantly greater c-Fos activation in DR DA neurons compared to subordinates.Fiber photometry revealed that DA neurons in both regions were activated during proactive push behaviors and inhibited during passive retreats,with DR neurons showing stronger activation during dominance-related actions.Chemogenetic inhibition of DR DA neurons in dominant mice reduced their social rank,whereas activation in subordinates elevated their rank.In contrast,chemogenetic modulation of VTA DA neurons had no significant effect on social dominance.Manipulation of DA neurons in both regions produced rank-dependent changes in specific anxiety-like behavioral phenotypes.These findings highlight the distinct roles of DR and VTA DA neurons in social hierarchy regulation,identifying DR DA neurons as a critical component in the modulation of social dominance.展开更多
Chronic visceral pain is a persistent and debilitating condition arising from dysfunction or sensitization of the visceral organs and their associated nervous pathways.Increasing evidence suggests that imbalances in c...Chronic visceral pain is a persistent and debilitating condition arising from dysfunction or sensitization of the visceral organs and their associated nervous pathways.Increasing evidence suggests that imbalances in central nervous system function play an essential role in the progression of visceral pain,but the exact mechanisms underlying the neural circuitry and molecular targets remain largely unexplored.In the present study,the ventral tegmental area(VTA)was shown to mediate visceral pain in mice.Visceral pain stimulation increased c-Fos expression and Ca2+activity of glutamatergic VTA neurons,and optogenetic modulation of glutamatergic VTA neurons altered visceral pain.In particular,the upregulation of NMDA receptor 2A(NR2A)subunits within the VTA resulted in visceral pain in mice.Administration of a selective NR2A inhibitor decreased the number of visceral pain-induced c-Fos positive neurons and attenuated visceral pain.Pharmacology combined with chemogenetics further demonstrated that glutamatergic VTA neurons regulated visceral pain behaviors based on NR2A.In summary,our findings demonstrated that the upregulation of NR2A in glutamatergic VTA neurons plays a critical role in visceral pain.These insights provide a foundation for further comprehension of the neural circuits and molecular targets involved in chronic visceral pain and may pave the way for targeted therapies in chronic visceral pain.展开更多
Objective The aim of the present study was not only to assess the retrograde degenerative changes in the dopaminergic neurons of the substantia nigra （SN） and ventral tegmental area （VTA） after injection of 6-hydr...Objective The aim of the present study was not only to assess the retrograde degenerative changes in the dopaminergic neurons of the substantia nigra （SN） and ventral tegmental area （VTA） after injection of 6-hydroxydopamine （6-OHDA） into the striatum, but also to use this 6-OHDA model of Parkinson＇s disease to explore the possible neuroprotective effect of R-apomorphine （R-APt）. Methods The partial lesion was obtained by intrastriatal administration of 6-OHDA. R- APt administration （10 mg/kg, s.c.） started 15 min prior to lesioning and continued daily for another 22 days post surgery. Testing was carried out 5 weeks after lesioning. We investigated the histology and associated behavior and neurochemical changes. Structural and functional deficits were quantified by tyrosine hydroxylase （TH） / Nissl-staining cell number counting, striatal dopamine （DA） content determination and amphetamine-induced rotation analysis. Results R-APt- treatment attenuated the amphetamine-induced ipsiversive rotation 5 weeks after the lesion induction. R-APt administra- tion for 22 days significantly reduced the size of the lesion at the level of the SN from 50% （control group） to 69%. Moreover, the cell shape resembled that observed in the intact animals. R-APt treatment significantly increased the number of cells in both the lesion and the intact sides of VTA by 60%, suggesting selective neurotrophic effect of R-APt in this area. Finally, R-APt-treatment significantly attenuated the 6-OHDA-induced striatal DA depletion and normalized dihydroxyphenylacetic acid （DOPAC）/DA ratios. Conclusion We conclude that R-APt has neuroprotective and pos- sible neurotrophic effect on a striatal lesion with 6-OHDA, suggesting that this drug may have rescuing properties in patients with early stage Parkinson＇s disease. These effects are more pronounced in VTA and enhance with duration of treatment.展开更多
Objective To observe the effect of acupuncture stimulation of the sacral segment on the excitability of the cerebral cortex and the activity of the urinary bladder and the involvement of the cholinergic neurons in the...Objective To observe the effect of acupuncture stimulation of the sacral segment on the excitability of the cerebral cortex and the activity of the urinary bladder and the involvement of the cholinergic neurons in the laterodorsal tegmental （LDT） nucleus of the brainstem in acupuncture-induced electroencephalogram （EEG） changes. Methods A total of 109 SD rats were used in the present study. Under anesthesia （urethane）, a pair of stainless steel electrodes was separately implanted into the frontal and parietal bony sutures to record EEG. Glass microelectrodes were used to record extracellular discharges of single neuron of the LDT nucleus in the brainstem. Urinary bladder pressure was recorded through a catheter inserted in the bladder and the contraction was induced by infusion of normal saline. A filiform acupuncture needle was inserted into the sacral segment Ecorresponding to Zhongliao （中髎BL 33）] and rotated manually for 1 min. Results In 27 rats whose bladder was full of normal saline, acupuncture stimulation of the sacral region suppressed the contraction activity of the bladder, the fast EEG with lower amplitude and higher frequency tuned into slow EEG with higher amplitude and lower frequency in 6 cases （22.2%）. The inhibitory effect occurred from 45 s to 12 min after acupuncture manipulation. In 82 rats whose bladder was empty, acupuncture stimulation caused the fast EEG to turn into slow EEG in 71 cases （86.6%）. Simultaneously, LDT cholinergic neurons reduced their firing rates from （2.9±1.5） Hz to （1.2±0.6） Hz （n = 12, P〈0.05）, and the reduction of LDT neuronal discharge was earlier in time than the change of EEG. Conclusion Acupuncture stimulation of the sacral region can lower the excitability of the cerebral cortex and suppress bladder activity, which is closely associated with its resultant inhibitory effect on the electrical activity of LDT cholinergic neurons.展开更多
Mesocorticolimbic dopaminergic(DA) neurons have been implicated in regulating nociception in chronic pain, yet the mechanisms are barely understood. Here, we found that chronic constructive injury(CCI) in mice increas...Mesocorticolimbic dopaminergic(DA) neurons have been implicated in regulating nociception in chronic pain, yet the mechanisms are barely understood. Here, we found that chronic constructive injury(CCI) in mice increased the firing activity and decreased the KCNQ channel-mediated M-currents in ventral tegmental area(VTA) DA neurons projecting to the nucleus accumbens(NAc). Chemogenetic inhibition of the VTA-to-NAc DA neurons alleviated CCI-induced thermal nociception.Opposite changes in the firing activity and M-currents were recorded in VTA DA neurons projecting to the medial prefrontal cortex(mPFC) but did not affect nociception. In addition, intra-VTA injection of retigabine, a KCNQ opener, while reversing the changes of the VTA-to-NAc DA neurons, alleviated CCI-induced nociception, and this was abolished by injecting exogenous BDNF into the NAc.Taken together, these findings highlight a vital role of KCNQ channel-mediated modulation of mesolimbic DA activity in regulating thermal nociception in the chronic pain state.展开更多
Up to 20%of women experience stress-related disorders during the postpartum period;however,little is known about the specific neural circuitry by which maternal stress exerts its negative impacts on mental health and ...Up to 20%of women experience stress-related disorders during the postpartum period;however,little is known about the specific neural circuitry by which maternal stress exerts its negative impacts on mental health and maternal caregiving behavior.Theoretically,such a circuitry should serve as an interface between the stress response system and maternal neural network,transmitting stress signals to the neural circuitry that mediates maternal behavior.In this paper,I propose that the lateral habenula(LHb)serves this interface function.Evidence shows that the LHb plays a key role in encoding stress-induced effects and in the pathophysiology of major depression and stressrelated anxiety,and thus may play a role in maternal behavior as part of the maternal brain network.I hypothesize that maternal stress acts upon the LHb and two of its major downstream targets,i.e.,ventral tegmental area(VTA)and dorsal raphe nucleus(DRN),compromising the maternal care and contributing to postpartum mental disorders.This hypothesis makes three predictions:(1)maternal stress enhances LHb neuronal activity;(2)activation of DRN-and VTA-projecting neurons in the LHb mimics the detrimental effects of maternal stress on maternal behavior;and(3)suppression of DRN-and VTA-projecting neurons in the LHb attenuates the detrimental effects of maternal stress on maternal care in stressed mothers.Confirmation of this hypothesis is expected to enhance our understanding of the neurocircuit mechanisms mediating stress effects on maternal behavior.展开更多
In the present article, the author proposes a new “D-cell hypothesis” for mesolimbic dopamine (DA) hyperactivity of schizophrenia, of which relevant molecular mechanism has not yet been known. The “D-cell” is defi...In the present article, the author proposes a new “D-cell hypothesis” for mesolimbic dopamine (DA) hyperactivity of schizophrenia, of which relevant molecular mechanism has not yet been known. The “D-cell” is defined as “the non-monoaminergic aromatic L-amino acid decarboxylase (AADC)-containing cell”. The D-cell contains AADC but not dopaminergic nor serotonergic. D-cells produce trace amines, and also take up amine precursors and convert them to amines by decarboxylation. The author reported “dopa-decarboxylating neurons specific to the human striatum”, that is, “D-neurons” in the human striatum, and preliminarily the number reduction of D-neurons in the striatum and nucleus accumbens of postmortem brains of patients with schizophrenia. Trace amine-associated receptor, type 1 (TAAR1), a subtype of trace amine receptors, having a large number of ligands, including tyramine, β-phenylethylamine (PEA), and methamphetamine, is a target receptor for the latest neuroleptic discovery. Recent studies have shown that the decreased stimulation of TAAR1 on cell membranes or nerve terminals of DA neurons in the midbrain ventral tegmental area (VTA) increased firing frequency of VTA DA neurons. In brains of schizophrenia, dysfunction of neural stem cells in the subventricular zone of lateral ventricle may cause reduction of the number of D-neurons in the striatum and nucleus accumbens, and may result in decrease of trace amine synthesis. The decrease of stimulation of TAAR1 on terminals of VTA DA neurons caused by trace amine reduction may increase firing frequency of VTA DA neurons, and may finally cause mesolimbic DA hyperactivity. This innovative theory, “D-cell hypothesis” might explain mesolimbic DA hyperactivity in pathogenesis of schizophrenia.展开更多
The author proposes a new “D-cell hypothesis” for mesolimbic dopamine (DA) hyperactivity of schizophrenia. The “D-cell” is defined as “non-monoaminergic aromatic L-amino acid decarboxylase (AADC)-containing cell...The author proposes a new “D-cell hypothesis” for mesolimbic dopamine (DA) hyperactivity of schizophrenia. The “D-cell” is defined as “non-monoaminergic aromatic L-amino acid decarboxylase (AADC)-containing cell”. D-cells produce trace amines, such as tyramine and β-phenylethylamine, and may also take up amine precursors and convert them to amines by decarboxylation. Trace amine-associated receptor, type 1 (TAAR1), a subtype of trace amine receptors, has a large number of ligands, including tyramine, β-phenylethylamine and methamphetamine, that influence on human mental states, and is now regarded to be a target receptor for novel neuroleptics. Recent studies revealed that the reduced stimulation of TAAR1 on DA neurons in the midbrain ventral tegmental area (VTA) increased firing frequency of VTA DA neurons. The author and her colleagues reported the decrease of D-neurons in the striatum and nucleus accumbens of postmortem brains of patients with schizophrenia. This may imply the decrease of trace amine synthesis, resulting the reduced stimulation of TAAR1 on terminals of midbrain VTA DA neurons, and may lead to mesolimbic DA hyperactivity in schizophrenia. The decrease of striatal D-neurons of postmortem brains of schizophrenia is supposed to be due to neural stem cell dysfunction in the subventricular zone of lateral ventricle. The decrease of striatal D-neurons and acts of TAAR1 signals on DA neurons-might explain mesolimbic DA hyperactivity of schizophrenia.展开更多
Neural stem cell (NSC) hypofunction is an etiological hypothesis of schizophrenia. Although dopamine (DA) dysfunction is also a widely accepted hypothesis, molecular background of mesolimbic DA hyperactivity has not y...Neural stem cell (NSC) hypofunction is an etiological hypothesis of schizophrenia. Although dopamine (DA) dysfunction is also a widely accepted hypothesis, molecular background of mesolimbic DA hyperactivity has not yet been well known. Here, the author proposes “D-cell hypothesis”, accounting for molecular basis of mesolimbic DA hyperactivity of schizophrenia, by NSC hypofunction and decrease of putative NSC-induced D-cells. The “D-cell” is defined as “non-monoaminergic aromatic L-amino acid decarboxylase (AADC)-containing cell”. D-cells produce trace amines, and also take up amine precursors and convert them to amines by decarboxylation. The author reported “dopa-decarboxylating neurons specific to the human striatum”, that is, “D-neurons” in the human striatum, and decrease of striatal D-neurons in patients with schizophrenia. Trace amine-associated receptor, type 1 (TAAR1), a subtype of trace amine receptors, having a quite number of ligands such as tyramine, β-phenylethylamine (PEA) and methamphetamine, has modulating functions on monoamine neurons. It has been known that reduced binding of ligands to TAAR1 receptors on DA terminal of DA neurons of the midbrain ventral tegmental area (VTA) increased firing frequency of VTA DA neurons. In brains of schizophrenia, NSC hypofunction in the subventricular zone of lateral ventricle may cause decrease of D-neurons in the striatum and nucleus accumbens, and may result in decrease of trace amine signals. Decrease of trace amine signals to TAAR1 on VTA DA neurons may increase firing frequency of VTA DA neurons, and may finally cause mesolimbic DA hyperactivity. Increased stimulation to DA D2 receptors of NSCs might suppress NSC proliferation, and may induce additional mesolimbic DA hyperactivity as well as D-cell decrease. This novel theory, “D-cell hypothesis”, possibly explains mesolimbic DA hyperactivity in pathogenesis of schizophrenia.展开更多
基金supported by the National Natural Science Foundation of China(81801366 and 82001453)and the National Key R&D Program of China(2018YFC2001901).
文摘Dopaminergic neurons in the ventral tegmental area(VTA)play an important role in cognition,emergence from anesthesia,reward,and aversion,and their projection to the cortex is a crucial part of the"bottom-up"ascending activating system.The prelimbic cortex(PrL)is one of the important projection regions of the VTA.However,the roles of dopaminergic neurons in the VTA and the VTADA–PrL pathway under sevoflurane anesthesia in rats remain unclear.In this study,we found that intraperitoneal injection and local microinjection of a dopamine D1 receptor agonist(Chloro-APB)into the PrL had an emergence-promoting effect on sevoflurane anesthesia in rats,while injection of a dopamine D1 receptor antagonist(SCH23390)deepened anesthesia.The results of chemogenetics combined with microinjection and optogenetics showed that activating the VTADA–PrL pathway prolonged the induction time and shortened the emergence time of anesthesia.These results demonstrate that the dopaminergic system in the VTA has an emergence-promoting effect and that the bottom-up VTADA–PrL pathway facilitates emergence from sevoflurane anesthesia.
基金supported by a grant from the Rafsanjan University of Medical Sciences(20/341/1395)
文摘Objective: To investigate the effect of crocin carotenoid on BNDF and CREB gene expression in the brain ventral tegmental area(VTA) and the serum level of BDNF in morphine-treated rats compared to control. Methods: In this study, 40 male Wistar rats(200-250 g) were used in 5 experimental groups: 1) non morphine treat rats(control); 2) non morphine-treated rats with 25 mg/kg crocin carotenoid(i.p., for 21 d); 3) morphine treated rats(10 mg/kg twice a day, s.c., 21 d); 4 and 5) morphine-treated rats with 12.5 and 25 mg/kg crocin carotenoid, respectively. By the end of research, BDNF and CREB expression was determined by real-time-PCR method. ELISA analysis was also applied for assessing the serum BDNF level. Results: The data indicated that morphine treatment could cause a significant decrease in BDNF and CREB gene expression(P<0.01 and P<0.001, respectively) in brain VTA as well as serum level of BDNF(P<0.01) in comparison to control group. Treatment with 25 mg/kg crocin carotenoid caused a significant enhancement in BDNF and CREF gene expression(P<0.01 and P<0.05, respectively) and serum level of BDNF(P<0.01) in morphine-treated rats in comparison to morphine-treated group. Conclusions: Regarding to obtained results, crocin carotenoid can inhibit unfavorable effects of morphine on the neural system to some extent through enhancing BDNF and CREB gene expression in brain VTA and serum level of BDNF.
基金supported by grants from National Natural Science Foundation of China(No.81071307,No.30872440,No.81171259)
文摘Neurons in the laterodorsal tegmentum (LDTg) and pedunculopontine tegmental nucleus (PPTg) play important roles in central autonomic circuits of the kidney. In this study, we used a combination of retrograde tracers pseudorabies virus (PRV)-614 and fluorescence immunohistochemistry to characterize the neuroanatomic substrate of PPTg and LDTg innervating the kidney in the mouse. PRV-614-infected neurons were retrogradely labeled in the rostral and middle parts of LDTg, and the middle and caudal parts of PPTg after tracer injection in the kidney. PRV-614/TPH double-labeled neurons were mainly localized in the rostral of LDTg, whereas PRV-614/TH neurons were scattered within the three parts of LDTg. PRV-614/TPH and PRV-614/TH neurons were located predominantly in the caudal of PPTg (cPPTg). These data provided direct neuroanatomical foundation for the identification of serotonergic and catecholaminergic projections from the mid-brain tegmentum to the kidney.
文摘Prior work has shown that systemic cocaine pretreatment augments cocaine conditioned place preference (CPP) in rats. In contrast, ghrelin receptor antagonism attenuates cocaine and amphetamine-induced CPP. In order to further investigate ghrelin’s role in dopamine-mediated reward, the present report examined whether pretreament with ghrelin, administered directly into the ventral tegmental area (VTA) of the midbrain, would potentiate the rewarding properties of cocaine as measured by CPP. Adult male Sprague-Dawley rats were given access to either side of the CPP chamber in order to determine initial side preferences. The rats were then restricted to either their non-preferred or preferred side over the course of conditioning which lasted for a total of 16 consecutive days. This was followed by a final test day to then reassess preference. On days where rats were confined to their non-preferred side, ghrelin (30-300 pmol) and cocaine (0.625-10 mg/kg IP) were administered immediately prior to the conditioning trial. On alternate days rats were treated with vehicle and placed into what was initially determined to be their preferred side. CPP was calculated as the difference in percentage of total time spent in the treatment-paired compartment during the post-conditioning session and the pre-conditioning session. Our results indicated that both cocaine and ghrelin elicited CPP and that ghrelin pretreatment potentiated the effect of cocaine on place preference. Overall, these findings provide additional support for the argument that ghrelin signaling within the VTA enhances the rewarding effects of psychostimulant compounds.
基金supported by the Major Project of Tobacco Biological Effects(552022AK0070,110202102014)。
文摘Nicotine is widely recognized as the primary contributor to tobacco dependence.Previous studies have indicated that molecular and behavioral responses to nicotine are primarily mediated by ventral tegmental area(VTA)neurons,and accumulating evidence suggests that glia play prominent roles in nicotine addiction.However,VTA neurons and glia have yet to be characterized at the transcriptional level during the progression of nicotine self-administration.Here,a male mouse model of nicotine self-administration is established and the timing of three critical phases(pre-addiction,addicting,and post-addiction phase)is characterized.Single-nucleus RNA sequencing in the VTA at each phase is performed to comprehensively classify specific cell subtypes.Adaptive changes occurred during the addicting and post-addiction phases,with the addicting phase displaying highly dynamic neuroplasticity that profoundly impacts the transcription in each cell subtype.Furthermore,significant transcriptional changes in energy metabolism-related genes are observed,accompanied by notable structural alterations in neuronal mitochondria during the progression of nicotine self-administration.The results provide insights into mechanisms underlying the progression of nicotine addiction,serving as an important resource for identifying potential molecular targets for nicotine cessation.
基金The project supported by the HKGRCGRF gran(t14111715)
文摘Rapid eye movement(REM)sleep behavior disorder(RBD)is a parasomnia that is featured by elevated motor behaviors and dream enactments during REM sleep.Clinical observations show that RBD bears significant relevance with several synucleinopathies such as Lewy body dementia and Parkinson disease(PD),and often develops prior to their diagnosis.Being a potential biomarker of PD,investigating the relationship of RBD symptoms and their emergence in developing PD would provide insight intoits pathogenesis.Here,in a chronic model of PD,rats with daily rotenone treatment exhibited key RBD features,including elevated sleep muscle tone,sleep fragmentation and EEG slowing at different time points.Based on detectedearly alpha synuclein aggregation and neural apoptosis in the sublaterodorsal tegmental nucleus(SLD),an area known to promote REM sleep and maintain sleep muscle atonia,the possible involvement of SLD glutamatergic neurons was interrogated.Via chemogenetic activation of SLD glutamatergic neurons,key RBD symptoms and EEG slowing in REM sleep were alleviated.These results are consistent with a progressive degeneration in REM sleep promoting pathways.Our findings provide a foundation for further studies into RBD and its relationship to neurodegenerative diseases.
文摘Methylphenidate (MPD) is considered as the first-line pharmacotherapy to treat ADHD. More recently, MPD has also been used as a cognitive enhancement recreationally. Its therapeutic effects are not fully understood, nor are the long term effects of the drug on brain development. The ventral tegmental area (VTA) neuronal activity was recorded from freely behaving adolescent rats using a wireless recording system. Five groups were used: saline, 0.6, 2.5, 5.0 and 10.0 mg/kg MPD. The experiment lasted for 10 days. This study demonstrated that VTA neurons respond to MPD in a dose response characteristic and the same dose of MPD can cause both behavioral sensitization and behavioral tolerance. The neuronal unit activity was evaluated based on the animals’ behavioral activity following chronic MPD administration. The study showed that the animals’ behavioral response to different acute MPD of 0.6, 2.5 and 10.0 mg/kg doses responded in a dose response characteristics. Moreover, the same chronic dose of 0.6, 2.5, and 10.0 mg/kg MPD elicits in some animals’ behavioral sensitization and in some others behavioral tolerance. Therefore, the neuronal activity recorded from animals expressing behavioral sensitization was analyzed separately from the neuronal activity recorded from of behaviorally tolerant animals and it was found that the VTA units of the behaviorally sensitization animals responded significantly different to the drug than those VTA units recorded from animals expressing behavioral tolerance.
基金grants from the Swedish Research Council (grant no. K2006-21X-04247-33-3 and 2009-2782)The Swedish brain foundation, LUA/ALF (grant no. 148251)
文摘The mesolimbic dopamine system consisting of dopaminergic neurons projecting from the ventral tegmental area (VTA) to the nucleus accumbens (N.Acc.) mediates the reinforcing effects of addictive drugs including alcohol. Given that VTA is a heterogeneous area and that alcohol, in rather low doses, interacts directly with ligand-gated ion channels, we hypothesised that low, rather than high, doses of alcohol into the VTA activate the mesolimbic dopamine system and that alcohol may have different effects in the anterior and posterior parts of the VTA. The present study was undertaken to investigate this hypothesis. The present series of experiment show that infusion of a low dose of alcohol (20 mM) into the anterior, but not posterior, part of the VTA increases accumbal dopamine release in rats. In addition, higher doses of alcohol (100 or 300 mM) into the anterior or posterior part of the VTA do not affect the release of dopamine in the N.Acc., suggesting that low doses of alcohol can activate the mesolimbic dopamine system via mechanisms in the VTA. These data contribute to understanding the neuronal mechanisms underlying the dependence-producing properties of alcohol and could tentatively contribute to that new treatment strategies for alcohol use disorder can be developed.
基金This work was supported by the National Natural Science Foundation of China(32192410,32071000,81870866,81571074,82230037,81971226,81620108008,82130034)the Foundation for Distinguished Young Scholars of ShaanXi(2019JC-21,2021JC-33)+1 种基金Young Scholar Project of the First Affiliated Hospital of Nanchang University(YFYPY202109)the Boost Plan of Xijing Hospital(XJZT21J01).
文摘Chronic pain often develops severe mood changes such as depression.However,how chronic pain leads to depression remains elusive and the mechanisms determining individuals’responses to depression are largely unexplored.Here we found that depression-like behaviors could only be observed in 67.9%of mice with chronic neuropathic pain,leaving 32.1%of mice with depression resilience.We determined that the spike discharges of the ventral tegmental area(VTA)-projecting lateral habenula(LHb)glutamatergic(Glu)neurons were sequentially increased in sham,resilient and susceptible mice,which consequently inhibited VTA dopaminergic(DA)neurons through a LHbGlu-VTAGABA-VTADA circuit.Furthermore,the LHbGlu-VTADA excitatory inputs were dampened via GABAB receptors in a pre-synaptic manner.Regulation of LHb-VTA pathway largely affected the development of depressive symptoms caused by chronic pain.Our study thus identifies a pivotal role of the LHb-VTA pathway in coupling chronic pain with depression and highlights the activity-dependent contribution of LHbGlu-to-VTADA inhibition in depressive behavioral regulation.
基金supported financially by the National Natural Science Foundation of China,No.82071272(to YZ).
文摘Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific,particularly involving the corticolimbic system,including the ventral tegmental area,nucleus accumbens,prefrontal cortex,amygdala,and hippocampus.Determining how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress psychopathology.In this review,we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of depression.We focused on associated molecular pathways and neural circuits,with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine circuit.We determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature,severity,and duration of stress,especially in the above-mentioned brain regions of the corticolimbic system.Therefore,BDNF might be a biological indicator regulating stress-related processes in various brain regions.
基金supported by grants from the National Natural Science Foundation of China(81871062)Guangdong Basic and Applied Basic Research Foundation(2024A1515012913)+1 种基金the Key Research Foundation of Guangdong Provincial Education Bureau(2023ZDZX2037)the Special Fund of Science and Technology Innovation Cultivation of Guangdong University Students(pdjh2024a238,pdjh2025ak133)。
文摘Dear Editor,Post-traumatic stress disorder(PTSD)is a chronic neuropsychiatric disorder triggered by severe traumatic events,characterized by persistent intrusive memories,emotional dysregulation,hyperarousal,and avoidance behaviors[1,2].PTSD is associated with significant gene expression changes in key brain regions,including the ventral tegmental area(VTA),which may underlie dysregulation of dopaminergic signaling and stress-related behaviors[3].
基金supported by the National Natural Science Foundation of China(32270529 to L.F.L.32270510 to F.D.T.)+2 种基金STI2030-Majior Projects(2022ZD0205101 to F.D.T.)Natural Science Foundation of Henan Province(252300420211 to Y.J.L.)Key Scientific Research Project of Higher Education Institutions in Henan Province(23A180001 to L.F.L.)#。
文摘Social hierarchies are central to the organizational structure of group-living species,shaping individual physiology,behavior,and social interactions.Dopaminergic(DA)systems,particularly within the ventral tegmental area(VTA)and dorsal raphe nucleus(DR),have been linked to motivation and competitive behaviors,yet their region-specific contributions to social dominance remain insufficiently defined.This study investigated the role of VTA and DR DA neurons in regulating social dominance in sexually naïve male C57BL/6J mice.Stable hierarchies were established using the tube test,after which both dominant and subordinate mice exhibited elevated c-Fos expression within the VTA and DR.Notably,dominant mice displayed significantly greater c-Fos activation in DR DA neurons compared to subordinates.Fiber photometry revealed that DA neurons in both regions were activated during proactive push behaviors and inhibited during passive retreats,with DR neurons showing stronger activation during dominance-related actions.Chemogenetic inhibition of DR DA neurons in dominant mice reduced their social rank,whereas activation in subordinates elevated their rank.In contrast,chemogenetic modulation of VTA DA neurons had no significant effect on social dominance.Manipulation of DA neurons in both regions produced rank-dependent changes in specific anxiety-like behavioral phenotypes.These findings highlight the distinct roles of DR and VTA DA neurons in social hierarchy regulation,identifying DR DA neurons as a critical component in the modulation of social dominance.
基金supported by grants from the National Natural Science Foundation of China(82401454 and 32230041)the Postdoctoral Fellowship Program of CPSF(GZC20231890)+1 种基金Zhangjiagang Technology Project for Youth(ZJGQNKJ202424)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China.
文摘Chronic visceral pain is a persistent and debilitating condition arising from dysfunction or sensitization of the visceral organs and their associated nervous pathways.Increasing evidence suggests that imbalances in central nervous system function play an essential role in the progression of visceral pain,but the exact mechanisms underlying the neural circuitry and molecular targets remain largely unexplored.In the present study,the ventral tegmental area(VTA)was shown to mediate visceral pain in mice.Visceral pain stimulation increased c-Fos expression and Ca2+activity of glutamatergic VTA neurons,and optogenetic modulation of glutamatergic VTA neurons altered visceral pain.In particular,the upregulation of NMDA receptor 2A(NR2A)subunits within the VTA resulted in visceral pain in mice.Administration of a selective NR2A inhibitor decreased the number of visceral pain-induced c-Fos positive neurons and attenuated visceral pain.Pharmacology combined with chemogenetics further demonstrated that glutamatergic VTA neurons regulated visceral pain behaviors based on NR2A.In summary,our findings demonstrated that the upregulation of NR2A in glutamatergic VTA neurons plays a critical role in visceral pain.These insights provide a foundation for further comprehension of the neural circuits and molecular targets involved in chronic visceral pain and may pave the way for targeted therapies in chronic visceral pain.
文摘Objective The aim of the present study was not only to assess the retrograde degenerative changes in the dopaminergic neurons of the substantia nigra （SN） and ventral tegmental area （VTA） after injection of 6-hydroxydopamine （6-OHDA） into the striatum, but also to use this 6-OHDA model of Parkinson＇s disease to explore the possible neuroprotective effect of R-apomorphine （R-APt）. Methods The partial lesion was obtained by intrastriatal administration of 6-OHDA. R- APt administration （10 mg/kg, s.c.） started 15 min prior to lesioning and continued daily for another 22 days post surgery. Testing was carried out 5 weeks after lesioning. We investigated the histology and associated behavior and neurochemical changes. Structural and functional deficits were quantified by tyrosine hydroxylase （TH） / Nissl-staining cell number counting, striatal dopamine （DA） content determination and amphetamine-induced rotation analysis. Results R-APt- treatment attenuated the amphetamine-induced ipsiversive rotation 5 weeks after the lesion induction. R-APt administra- tion for 22 days significantly reduced the size of the lesion at the level of the SN from 50% （control group） to 69%. Moreover, the cell shape resembled that observed in the intact animals. R-APt treatment significantly increased the number of cells in both the lesion and the intact sides of VTA by 60%, suggesting selective neurotrophic effect of R-APt in this area. Finally, R-APt-treatment significantly attenuated the 6-OHDA-induced striatal DA depletion and normalized dihydroxyphenylacetic acid （DOPAC）/DA ratios. Conclusion We conclude that R-APt has neuroprotective and pos- sible neurotrophic effect on a striatal lesion with 6-OHDA, suggesting that this drug may have rescuing properties in patients with early stage Parkinson＇s disease. These effects are more pronounced in VTA and enhance with duration of treatment.
文摘Objective To observe the effect of acupuncture stimulation of the sacral segment on the excitability of the cerebral cortex and the activity of the urinary bladder and the involvement of the cholinergic neurons in the laterodorsal tegmental （LDT） nucleus of the brainstem in acupuncture-induced electroencephalogram （EEG） changes. Methods A total of 109 SD rats were used in the present study. Under anesthesia （urethane）, a pair of stainless steel electrodes was separately implanted into the frontal and parietal bony sutures to record EEG. Glass microelectrodes were used to record extracellular discharges of single neuron of the LDT nucleus in the brainstem. Urinary bladder pressure was recorded through a catheter inserted in the bladder and the contraction was induced by infusion of normal saline. A filiform acupuncture needle was inserted into the sacral segment Ecorresponding to Zhongliao （中髎BL 33）] and rotated manually for 1 min. Results In 27 rats whose bladder was full of normal saline, acupuncture stimulation of the sacral region suppressed the contraction activity of the bladder, the fast EEG with lower amplitude and higher frequency tuned into slow EEG with higher amplitude and lower frequency in 6 cases （22.2%）. The inhibitory effect occurred from 45 s to 12 min after acupuncture manipulation. In 82 rats whose bladder was empty, acupuncture stimulation caused the fast EEG to turn into slow EEG in 71 cases （86.6%）. Simultaneously, LDT cholinergic neurons reduced their firing rates from （2.9±1.5） Hz to （1.2±0.6） Hz （n = 12, P〈0.05）, and the reduction of LDT neuronal discharge was earlier in time than the change of EEG. Conclusion Acupuncture stimulation of the sacral region can lower the excitability of the cerebral cortex and suppress bladder activity, which is closely associated with its resultant inhibitory effect on the electrical activity of LDT cholinergic neurons.
基金supported by grants from the National Natural Science Foundation of China (31771161, 81720108013, 81230025, 81200859 and 81801096)Key Project of Nature Science Foundation of Jiangsu Education Department (17KJA320005)+4 种基金Natural Science Foundation of Jiangsu Province (BK20171159)the Qing-Lan Project of Jiangsu, the Six Talent Summit Project of Jiangsuthe 333 High-level Personnel Training Project of Jiangsuthe Priority Academic Program Development of Jiangsu Higher Education Institutions, the Jiangsu Provincial Special Program of Medical Science (BL2014029)the Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX19–2241 and KYCX20_2449), China。
文摘Mesocorticolimbic dopaminergic(DA) neurons have been implicated in regulating nociception in chronic pain, yet the mechanisms are barely understood. Here, we found that chronic constructive injury(CCI) in mice increased the firing activity and decreased the KCNQ channel-mediated M-currents in ventral tegmental area(VTA) DA neurons projecting to the nucleus accumbens(NAc). Chemogenetic inhibition of the VTA-to-NAc DA neurons alleviated CCI-induced thermal nociception.Opposite changes in the firing activity and M-currents were recorded in VTA DA neurons projecting to the medial prefrontal cortex(mPFC) but did not affect nociception. In addition, intra-VTA injection of retigabine, a KCNQ opener, while reversing the changes of the VTA-to-NAc DA neurons, alleviated CCI-induced nociception, and this was abolished by injecting exogenous BDNF into the NAc.Taken together, these findings highlight a vital role of KCNQ channel-mediated modulation of mesolimbic DA activity in regulating thermal nociception in the chronic pain state.
文摘Up to 20%of women experience stress-related disorders during the postpartum period;however,little is known about the specific neural circuitry by which maternal stress exerts its negative impacts on mental health and maternal caregiving behavior.Theoretically,such a circuitry should serve as an interface between the stress response system and maternal neural network,transmitting stress signals to the neural circuitry that mediates maternal behavior.In this paper,I propose that the lateral habenula(LHb)serves this interface function.Evidence shows that the LHb plays a key role in encoding stress-induced effects and in the pathophysiology of major depression and stressrelated anxiety,and thus may play a role in maternal behavior as part of the maternal brain network.I hypothesize that maternal stress acts upon the LHb and two of its major downstream targets,i.e.,ventral tegmental area(VTA)and dorsal raphe nucleus(DRN),compromising the maternal care and contributing to postpartum mental disorders.This hypothesis makes three predictions:(1)maternal stress enhances LHb neuronal activity;(2)activation of DRN-and VTA-projecting neurons in the LHb mimics the detrimental effects of maternal stress on maternal behavior;and(3)suppression of DRN-and VTA-projecting neurons in the LHb attenuates the detrimental effects of maternal stress on maternal care in stressed mothers.Confirmation of this hypothesis is expected to enhance our understanding of the neurocircuit mechanisms mediating stress effects on maternal behavior.
文摘In the present article, the author proposes a new “D-cell hypothesis” for mesolimbic dopamine (DA) hyperactivity of schizophrenia, of which relevant molecular mechanism has not yet been known. The “D-cell” is defined as “the non-monoaminergic aromatic L-amino acid decarboxylase (AADC)-containing cell”. The D-cell contains AADC but not dopaminergic nor serotonergic. D-cells produce trace amines, and also take up amine precursors and convert them to amines by decarboxylation. The author reported “dopa-decarboxylating neurons specific to the human striatum”, that is, “D-neurons” in the human striatum, and preliminarily the number reduction of D-neurons in the striatum and nucleus accumbens of postmortem brains of patients with schizophrenia. Trace amine-associated receptor, type 1 (TAAR1), a subtype of trace amine receptors, having a large number of ligands, including tyramine, β-phenylethylamine (PEA), and methamphetamine, is a target receptor for the latest neuroleptic discovery. Recent studies have shown that the decreased stimulation of TAAR1 on cell membranes or nerve terminals of DA neurons in the midbrain ventral tegmental area (VTA) increased firing frequency of VTA DA neurons. In brains of schizophrenia, dysfunction of neural stem cells in the subventricular zone of lateral ventricle may cause reduction of the number of D-neurons in the striatum and nucleus accumbens, and may result in decrease of trace amine synthesis. The decrease of stimulation of TAAR1 on terminals of VTA DA neurons caused by trace amine reduction may increase firing frequency of VTA DA neurons, and may finally cause mesolimbic DA hyperactivity. This innovative theory, “D-cell hypothesis” might explain mesolimbic DA hyperactivity in pathogenesis of schizophrenia.
文摘The author proposes a new “D-cell hypothesis” for mesolimbic dopamine (DA) hyperactivity of schizophrenia. The “D-cell” is defined as “non-monoaminergic aromatic L-amino acid decarboxylase (AADC)-containing cell”. D-cells produce trace amines, such as tyramine and β-phenylethylamine, and may also take up amine precursors and convert them to amines by decarboxylation. Trace amine-associated receptor, type 1 (TAAR1), a subtype of trace amine receptors, has a large number of ligands, including tyramine, β-phenylethylamine and methamphetamine, that influence on human mental states, and is now regarded to be a target receptor for novel neuroleptics. Recent studies revealed that the reduced stimulation of TAAR1 on DA neurons in the midbrain ventral tegmental area (VTA) increased firing frequency of VTA DA neurons. The author and her colleagues reported the decrease of D-neurons in the striatum and nucleus accumbens of postmortem brains of patients with schizophrenia. This may imply the decrease of trace amine synthesis, resulting the reduced stimulation of TAAR1 on terminals of midbrain VTA DA neurons, and may lead to mesolimbic DA hyperactivity in schizophrenia. The decrease of striatal D-neurons of postmortem brains of schizophrenia is supposed to be due to neural stem cell dysfunction in the subventricular zone of lateral ventricle. The decrease of striatal D-neurons and acts of TAAR1 signals on DA neurons-might explain mesolimbic DA hyperactivity of schizophrenia.
文摘Neural stem cell (NSC) hypofunction is an etiological hypothesis of schizophrenia. Although dopamine (DA) dysfunction is also a widely accepted hypothesis, molecular background of mesolimbic DA hyperactivity has not yet been well known. Here, the author proposes “D-cell hypothesis”, accounting for molecular basis of mesolimbic DA hyperactivity of schizophrenia, by NSC hypofunction and decrease of putative NSC-induced D-cells. The “D-cell” is defined as “non-monoaminergic aromatic L-amino acid decarboxylase (AADC)-containing cell”. D-cells produce trace amines, and also take up amine precursors and convert them to amines by decarboxylation. The author reported “dopa-decarboxylating neurons specific to the human striatum”, that is, “D-neurons” in the human striatum, and decrease of striatal D-neurons in patients with schizophrenia. Trace amine-associated receptor, type 1 (TAAR1), a subtype of trace amine receptors, having a quite number of ligands such as tyramine, β-phenylethylamine (PEA) and methamphetamine, has modulating functions on monoamine neurons. It has been known that reduced binding of ligands to TAAR1 receptors on DA terminal of DA neurons of the midbrain ventral tegmental area (VTA) increased firing frequency of VTA DA neurons. In brains of schizophrenia, NSC hypofunction in the subventricular zone of lateral ventricle may cause decrease of D-neurons in the striatum and nucleus accumbens, and may result in decrease of trace amine signals. Decrease of trace amine signals to TAAR1 on VTA DA neurons may increase firing frequency of VTA DA neurons, and may finally cause mesolimbic DA hyperactivity. Increased stimulation to DA D2 receptors of NSCs might suppress NSC proliferation, and may induce additional mesolimbic DA hyperactivity as well as D-cell decrease. This novel theory, “D-cell hypothesis”, possibly explains mesolimbic DA hyperactivity in pathogenesis of schizophrenia.
