Synapses are key structures in neural networks,and are involved in learning and memory in the central nervous system.Investigating synaptogenesis and synaptic aging is important in understanding neural development and...Synapses are key structures in neural networks,and are involved in learning and memory in the central nervous system.Investigating synaptogenesis and synaptic aging is important in understanding neural development and neural degeneration in diseases such as Alzheimer disease and Parkinson’s disease.Our previous study found that synaptogenesis and synaptic maturation were harmonized with brain development and maturation.However,synaptic damage and loss in the aging cerebellum are not well understood.This study was designed to investigate the occurrence of synaptic aging in the cerebellum by observing the ultrastructural changes of dendritic spines and synapses in cerebellar Purkinje cells of aging mice.Immunocytochemistry,Di I diolistic assays,and transmission electron microscopy were used to visualize the morphological characteristics of synaptic buttons,dendritic spines and synapses of Purkinje cells in mice at various ages.With synaptic aging in the cerebellum,dendritic spines and synaptic buttons were lost,and the synaptic ultrastructure was altered,including a reduction in the number of synaptic vesicles and mitochondria in presynaptic termini and smaller thin specialized zones in pre-and post-synaptic membranes.These findings confirm that synaptic morphology and function is disrupted in aging synapses,which may be an important pathological cause of neurodegenerative diseases.展开更多
Summary： The regulation of astroglia on synaptic plasticity in the CA1 region of rat hippocampus was examined. Rats were divided into three groups： the newly horn （〈24 h）, the juvenile （28-30 days） and the adul...Summary： The regulation of astroglia on synaptic plasticity in the CA1 region of rat hippocampus was examined. Rats were divided into three groups： the newly horn （〈24 h）, the juvenile （28-30 days） and the adult groups （90-100 days）, with each group having 20 animals. The CA1 region of rat hippocampus was immunohistochemically and electron-microscopically examined, respectively, for the growth of astroglia and the ultrastructure of synapses. The high performance liquid chromatography was employed to determine the cholesterol content of rat hippocampus. In the newly-born rats, a large number of neurons were noted in the hippocampal CA1 region of the newly-born rats, and few astroglia and no synaptic structure were observed. In the juvenile group, a few astroglias and some immature synapses were found, which were less than those in adult rats （P〈0.01）. The cholesterol content was 2.92±0.03 mg/g, 11.20±3.41 mg/g and 12.91±1.25 mg/g for newly born, the juvenile and the adult groups, respectively, with the differences among them being statistically significant （P〈0.01）. Our study suggests that the astrocytes may play an important role in the synaptic formation and functional maturity of hippocampal neurons, which may be related to the secretion of cholesterol from astrocytes.展开更多
Objective: To observe the effect of electroacupuncture (EA) on synaptic structure of hippocampal nerve felts and synaptophysin(SYN)expression in rats with cerebral ischemic injury. Methods: Sixty Wistar rats were rand...Objective: To observe the effect of electroacupuncture (EA) on synaptic structure of hippocampal nerve felts and synaptophysin(SYN)expression in rats with cerebral ischemic injury. Methods: Sixty Wistar rats were randomized into sham-operation group, cerebral ischemia (CI) group and EA group, each of which was further divided into 1week (W) and 5W subgroups. CI injury model was established by occlusion of the bilateral common carotid arteries. 'Baihui'(百会 GV 20), 'Dazhui' (大椎 GV 14), 'Renzhong'(人中 GV 26) and 'Guangyuan'(关会 CV 4) were punctured and stimulated electrically. The brain tissue sections containing hippocampus region were stained with immu nohistochemical technique and observed under light microscope and transmission electronic microscope. Results: After CI, the ischemic injury as degeneration of the presynapse compositions, decrease of the synaptic numeral density, and low expression of SYN were observed in hippocampal CA1 area. By the 5th week after CI, the neonatal synapses of Cl and EA groups appeared, and SYN expression was upregulated. In EA group, the recovery of the numeral density of synapses was especially noticeable, being 93.8% of that of sham-operation group and significantly higher than that in Cl group (P<0.01). Compared with sham-operation group, the calibrated optical density (COD) values of SYN increased to 70% in CI group, and 93.3% in EA group, and COD value in EA group was significantly higher than that in Cl group (P<0.01). Conclusion: EA can function in promoting synaptic regeneration and enhancing and perfecting the actions of the reconstructed synapses in hippocampal CA1 area in Cl rats.展开更多
基金supported by the Science and Technology Projects of Henan Province of China,No.172102310001the Biology Advantage Discipline Fund of Henan Province of China
文摘Synapses are key structures in neural networks,and are involved in learning and memory in the central nervous system.Investigating synaptogenesis and synaptic aging is important in understanding neural development and neural degeneration in diseases such as Alzheimer disease and Parkinson’s disease.Our previous study found that synaptogenesis and synaptic maturation were harmonized with brain development and maturation.However,synaptic damage and loss in the aging cerebellum are not well understood.This study was designed to investigate the occurrence of synaptic aging in the cerebellum by observing the ultrastructural changes of dendritic spines and synapses in cerebellar Purkinje cells of aging mice.Immunocytochemistry,Di I diolistic assays,and transmission electron microscopy were used to visualize the morphological characteristics of synaptic buttons,dendritic spines and synapses of Purkinje cells in mice at various ages.With synaptic aging in the cerebellum,dendritic spines and synaptic buttons were lost,and the synaptic ultrastructure was altered,including a reduction in the number of synaptic vesicles and mitochondria in presynaptic termini and smaller thin specialized zones in pre-and post-synaptic membranes.These findings confirm that synaptic morphology and function is disrupted in aging synapses,which may be an important pathological cause of neurodegenerative diseases.
文摘Summary： The regulation of astroglia on synaptic plasticity in the CA1 region of rat hippocampus was examined. Rats were divided into three groups： the newly horn （〈24 h）, the juvenile （28-30 days） and the adult groups （90-100 days）, with each group having 20 animals. The CA1 region of rat hippocampus was immunohistochemically and electron-microscopically examined, respectively, for the growth of astroglia and the ultrastructure of synapses. The high performance liquid chromatography was employed to determine the cholesterol content of rat hippocampus. In the newly-born rats, a large number of neurons were noted in the hippocampal CA1 region of the newly-born rats, and few astroglia and no synaptic structure were observed. In the juvenile group, a few astroglias and some immature synapses were found, which were less than those in adult rats （P〈0.01）. The cholesterol content was 2.92±0.03 mg/g, 11.20±3.41 mg/g and 12.91±1.25 mg/g for newly born, the juvenile and the adult groups, respectively, with the differences among them being statistically significant （P〈0.01）. Our study suggests that the astrocytes may play an important role in the synaptic formation and functional maturity of hippocampal neurons, which may be related to the secretion of cholesterol from astrocytes.
文摘Objective: To observe the effect of electroacupuncture (EA) on synaptic structure of hippocampal nerve felts and synaptophysin(SYN)expression in rats with cerebral ischemic injury. Methods: Sixty Wistar rats were randomized into sham-operation group, cerebral ischemia (CI) group and EA group, each of which was further divided into 1week (W) and 5W subgroups. CI injury model was established by occlusion of the bilateral common carotid arteries. 'Baihui'(百会 GV 20), 'Dazhui' (大椎 GV 14), 'Renzhong'(人中 GV 26) and 'Guangyuan'(关会 CV 4) were punctured and stimulated electrically. The brain tissue sections containing hippocampus region were stained with immu nohistochemical technique and observed under light microscope and transmission electronic microscope. Results: After CI, the ischemic injury as degeneration of the presynapse compositions, decrease of the synaptic numeral density, and low expression of SYN were observed in hippocampal CA1 area. By the 5th week after CI, the neonatal synapses of Cl and EA groups appeared, and SYN expression was upregulated. In EA group, the recovery of the numeral density of synapses was especially noticeable, being 93.8% of that of sham-operation group and significantly higher than that in Cl group (P<0.01). Compared with sham-operation group, the calibrated optical density (COD) values of SYN increased to 70% in CI group, and 93.3% in EA group, and COD value in EA group was significantly higher than that in Cl group (P<0.01). Conclusion: EA can function in promoting synaptic regeneration and enhancing and perfecting the actions of the reconstructed synapses in hippocampal CA1 area in Cl rats.
