Aim: Datura stramonium (DS) is a known hallucinogen and depressant of the central nervous system, but it is commonly used in alcoholic beverages to increase intoxication. Pharmacological, physiological and ultra-struc...Aim: Datura stramonium (DS) is a known hallucinogen and depressant of the central nervous system, but it is commonly used in alcoholic beverages to increase intoxication. Pharmacological, physiological and ultra-structural studies have demonstrated the neurotoxicity of this drug inanimals and humans at high doses. The present study investigated the histological patterns of neurodegeneration of frontal cortex (FC) neurons in Wistar rats treated with high doses of DS seed extract. Materials and methods: Ethanolic extract of DS dried seeds was diluted in normal saline and administered to male and female Wistar rats weighing 200 g - 250 g. The animals were first placed in three groups which were further sub-divided into four sub-groups. The treated sub-groups received intraperitoneal administration (i.p.) of 750 mg/kg of diluted DS seed extract once daily in group 1, twice daily (1500 mg/kg/day) in group 2 and thrice daily (2250 mg/kg/day) in group 3. The treatment was carried out for 4 weeks while the control groups received normal saline during the same period. The rats were euthanized and sections of the frontal cortices of the brain were histologically processed from all groups. Silver impregnation stain for degenerating axons and neurons was used to elucidate the pattern of degeneration induced by DS seed extract on the neurons of the FC. Results: The results of intraperitoneal administration of DS extract showed no changes in groups 1 & 2 treated rats while group 3 showed a significant pattern of histological changes like axonal atrophy, vacuolization and neuronal deaths in the frontal cortices neurons compared to the controls. Conclusion: DS may have a specific pattern of neurodegeneration at higher doses of administration. This could provide a useful model in understanding how DS intoxication can affect frontal cortex neurons with an implication of neurological disorders, mental diseases and behavioural deficits.展开更多
AIM: To study glutamine synthetase (GS) activity and glutamate uptake in the hippocampus and frontal cortex (FC) from rats with prehepatic portal vein hypertension. METHODS: Male Wistar rats were divided into shamoper...AIM: To study glutamine synthetase (GS) activity and glutamate uptake in the hippocampus and frontal cortex (FC) from rats with prehepatic portal vein hypertension. METHODS: Male Wistar rats were divided into shamoperated group and a portal hypertension (PH) group with a regulated stricture of the portal vein. Animals were sacrificed by decapitation 14 d after portal vein stricture. GS activity was determined in the hippocampus and FC. Specific uptake of radiolabeled L-glutamate was studied using synaptosome-enriched fractions that were freshly prepared from both brain areas. RESULTS: We observed that the activity of GS increased in the hippocampus of PH rats, as compared to control animals, and decreased in the FC. A significant decrease in glutamate uptake was found in both brain areas, and was more marked in the hippocampus. The decrease in glutamate uptake might have been caused by a deficient transport function, signif icantly and persistent increase in this excitatory neurotransmitter activity. CONCLUSION: The presence of moderate ammonia blood levels may add to the toxicity of excitotoxic glutamate in the brain, which causes alterations in brain function. Portal vein stricture that causes portal hypertension modif ies the normal function in some brain regions.展开更多
The frontal pole cortex(FPC)plays key roles in various higher-order functions and is highly developed in non-human primates.An essential missing piece of information is the detailed anatomical connections for finer pa...The frontal pole cortex(FPC)plays key roles in various higher-order functions and is highly developed in non-human primates.An essential missing piece of information is the detailed anatomical connections for finer parcellation of the macaque FPC than provided by the previous tracer results.This is important for understanding the functional architecture of the cerebral cortex.Here,combining cross-validation and principal component analysis,we formed a tractography-based parcellation scheme that applied a machine learning algorithm to divide the macaque FPC(2 males and 6 females)into eight subareas using high-resolution diffusion magnetic resonance imaging with the 9.4 T Bruker system,and then revealed their subregional connections.Furthermore,we applied improved hierarchical clustering to the obtained parcels to probe the modular structure of the subregions,and found that the dorsolateral FPC,which contains an extension to the medial FPC,was mainly connected to regions of the default-mode network.The ventral FPC was mainly involved in the social-interaction network and the dorsal FPC in the metacognitive network.These results enhance our understanding of the anatomy and circuitry of the macaque brain,and contribute to FPC-related clinical research.展开更多
This paper reports that lesions of the medial frontal cortex (MFC) caused behavioral deficit in rats and that this deficit could be attenuated by a well formulated treatment with Org2766, an analog of ACTH- (4-9). Wis...This paper reports that lesions of the medial frontal cortex (MFC) caused behavioral deficit in rats and that this deficit could be attenuated by a well formulated treatment with Org2766, an analog of ACTH- (4-9). Wistar rats were distributed in 3 groups: MFC lesion treated with saline (M-N); MFC lesion treated with Org2766 (MO);and sham-operation treated with saline (S). Repeated Org2766 or saline injection commenced from the day of surgery and lasted for 1 3 days. After surgery. the rats were trained in a passive avoidance task and then in an active avoidance task. MFC lesions were found to be strongly associated with behavioral deficits. The M-N group rats displayed poor retention of the passive avoidance response and showed much slower learning of the active avoidance task as compared to S group rats. The result showed that chronic Org2766 administration improved the behavioral performance of both tasks in MFC lesioned rats. The also revealed that the superoxide dismutase (SOD)activity was significantly increased in the M-O group as compared to the M-N group 15 days after surgery. The possible mechanisms related to the beneficial effect of Org2766 on cortex damage are discussed.展开更多
Stimulation at specific acupoints can activate cortical regions in human subjects.Previous studies have mainly focused on a single brain region.However,the brain is a network and many brain regions participate in the ...Stimulation at specific acupoints can activate cortical regions in human subjects.Previous studies have mainly focused on a single brain region.However,the brain is a network and many brain regions participate in the same task.The study of a single brain region alone cannot clearly explain any brain-related issues.Therefore,for the present study,magnetic stimulation was used to stimulate the Neiguan（PC6） acupoint,and 32-channel electroencephalography data were recorded before and after stimulation.Brain functional networks were constructed based on electroencephalography data to determine the relationship between magnetic stimulation at the PC6 acupoint and cortical excitability.Results indicated that magnetic stimulation at the PC6 acupoint increased connections between cerebral cortex regions.展开更多
文摘Aim: Datura stramonium (DS) is a known hallucinogen and depressant of the central nervous system, but it is commonly used in alcoholic beverages to increase intoxication. Pharmacological, physiological and ultra-structural studies have demonstrated the neurotoxicity of this drug inanimals and humans at high doses. The present study investigated the histological patterns of neurodegeneration of frontal cortex (FC) neurons in Wistar rats treated with high doses of DS seed extract. Materials and methods: Ethanolic extract of DS dried seeds was diluted in normal saline and administered to male and female Wistar rats weighing 200 g - 250 g. The animals were first placed in three groups which were further sub-divided into four sub-groups. The treated sub-groups received intraperitoneal administration (i.p.) of 750 mg/kg of diluted DS seed extract once daily in group 1, twice daily (1500 mg/kg/day) in group 2 and thrice daily (2250 mg/kg/day) in group 3. The treatment was carried out for 4 weeks while the control groups received normal saline during the same period. The rats were euthanized and sections of the frontal cortices of the brain were histologically processed from all groups. Silver impregnation stain for degenerating axons and neurons was used to elucidate the pattern of degeneration induced by DS seed extract on the neurons of the FC. Results: The results of intraperitoneal administration of DS extract showed no changes in groups 1 & 2 treated rats while group 3 showed a significant pattern of histological changes like axonal atrophy, vacuolization and neuronal deaths in the frontal cortices neurons compared to the controls. Conclusion: DS may have a specific pattern of neurodegeneration at higher doses of administration. This could provide a useful model in understanding how DS intoxication can affect frontal cortex neurons with an implication of neurological disorders, mental diseases and behavioural deficits.
基金Supported by Grant B013 from the University of Buenos Aires, Argentina and PIP 5869 from National Research Council of Argentina
文摘AIM: To study glutamine synthetase (GS) activity and glutamate uptake in the hippocampus and frontal cortex (FC) from rats with prehepatic portal vein hypertension. METHODS: Male Wistar rats were divided into shamoperated group and a portal hypertension (PH) group with a regulated stricture of the portal vein. Animals were sacrificed by decapitation 14 d after portal vein stricture. GS activity was determined in the hippocampus and FC. Specific uptake of radiolabeled L-glutamate was studied using synaptosome-enriched fractions that were freshly prepared from both brain areas. RESULTS: We observed that the activity of GS increased in the hippocampus of PH rats, as compared to control animals, and decreased in the FC. A significant decrease in glutamate uptake was found in both brain areas, and was more marked in the hippocampus. The decrease in glutamate uptake might have been caused by a deficient transport function, signif icantly and persistent increase in this excitatory neurotransmitter activity. CONCLUSION: The presence of moderate ammonia blood levels may add to the toxicity of excitotoxic glutamate in the brain, which causes alterations in brain function. Portal vein stricture that causes portal hypertension modif ies the normal function in some brain regions.
基金the National Natural Science Foundation of China(91432302 and 31620103905)the Science Frontier Program of the Chinese Academy of Sciences(QYZDJ-SSW-SMC019)+3 种基金the National Key R&D Program of China(2017YFA0105203)Beijing Municipal Science and Technology Commission(Z161100000216152,Z161100000216139,Z181100001518004and Z171100000117002)the Beijing Brain Initiative of Beijing Municipal Science and Technology Commission(Z181100001518004)the Guangdong Pearl River Talents Plan(2016ZT06S220)。
文摘The frontal pole cortex(FPC)plays key roles in various higher-order functions and is highly developed in non-human primates.An essential missing piece of information is the detailed anatomical connections for finer parcellation of the macaque FPC than provided by the previous tracer results.This is important for understanding the functional architecture of the cerebral cortex.Here,combining cross-validation and principal component analysis,we formed a tractography-based parcellation scheme that applied a machine learning algorithm to divide the macaque FPC(2 males and 6 females)into eight subareas using high-resolution diffusion magnetic resonance imaging with the 9.4 T Bruker system,and then revealed their subregional connections.Furthermore,we applied improved hierarchical clustering to the obtained parcels to probe the modular structure of the subregions,and found that the dorsolateral FPC,which contains an extension to the medial FPC,was mainly connected to regions of the default-mode network.The ventral FPC was mainly involved in the social-interaction network and the dorsal FPC in the metacognitive network.These results enhance our understanding of the anatomy and circuitry of the macaque brain,and contribute to FPC-related clinical research.
文摘This paper reports that lesions of the medial frontal cortex (MFC) caused behavioral deficit in rats and that this deficit could be attenuated by a well formulated treatment with Org2766, an analog of ACTH- (4-9). Wistar rats were distributed in 3 groups: MFC lesion treated with saline (M-N); MFC lesion treated with Org2766 (MO);and sham-operation treated with saline (S). Repeated Org2766 or saline injection commenced from the day of surgery and lasted for 1 3 days. After surgery. the rats were trained in a passive avoidance task and then in an active avoidance task. MFC lesions were found to be strongly associated with behavioral deficits. The M-N group rats displayed poor retention of the passive avoidance response and showed much slower learning of the active avoidance task as compared to S group rats. The result showed that chronic Org2766 administration improved the behavioral performance of both tasks in MFC lesioned rats. The also revealed that the superoxide dismutase (SOD)activity was significantly increased in the M-O group as compared to the M-N group 15 days after surgery. The possible mechanisms related to the beneficial effect of Org2766 on cortex damage are discussed.
基金supported by the Outstanding Youth Science and Technology Innovation Fund of Hebei University of Technology,No.2013007the Specialized Research Fund for the Doctoral Program of Higher Education of China,No.20131317120007+1 种基金the Natural Science Foundation of Hebei Province in China,No.H2013202176the Natural Science Foundation of China,No.31400844,51377045,61571180 and 31300818
文摘Stimulation at specific acupoints can activate cortical regions in human subjects.Previous studies have mainly focused on a single brain region.However,the brain is a network and many brain regions participate in the same task.The study of a single brain region alone cannot clearly explain any brain-related issues.Therefore,for the present study,magnetic stimulation was used to stimulate the Neiguan（PC6） acupoint,and 32-channel electroencephalography data were recorded before and after stimulation.Brain functional networks were constructed based on electroencephalography data to determine the relationship between magnetic stimulation at the PC6 acupoint and cortical excitability.Results indicated that magnetic stimulation at the PC6 acupoint increased connections between cerebral cortex regions.
