Electrical stimulation of the median nerve is a noninvasive technique that facilitates awakening from coma. In rats with traumatic brain injury-induced coma, median nerve stimulation markedly enhances prefrontal corte...Electrical stimulation of the median nerve is a noninvasive technique that facilitates awakening from coma. In rats with traumatic brain injury-induced coma, median nerve stimulation markedly enhances prefrontal cortex expression of orexin-A and its receptor, orexin receptor 1. To further understand the mechanism underlying wakefulness mediated by electrical stimulation of the median nerve, we evaluated its effects on the expression of the N-methyl-D-aspartate receptor subunit NR1 in the prefrontal cortex in rat models of traumatic brain injury-induced coma, using immunohistochemistry and western blot assays. In rats with traumatic brain injury, NR1 expression increased with time after injury. Rats that underwent electrical stimulation of the median nerve（30 Hz, 0.5 ms, 1.0 m A for 15 minutes） showed elevated NR1 expression and greater recovery of consciousness than those without stimulation. These effects were reduced by intracerebroventricular injection of the orexin receptor 1 antagonist SB334867. Our results indicate that electrical stimulation of the median nerve promotes recovery from traumatic brain injury-induced coma by increasing prefrontal cortex NR1 expression via an orexin-A-mediated pathway.展开更多
Objective: To investigate effects of developmental lead exposure on nitric oxide synthase (NOS) activity in different brain regions and on N-methyl-D-aspartate (NMDA) receptor mRNA expression in the hippocampus of rat...Objective: To investigate effects of developmental lead exposure on nitric oxide synthase (NOS) activity in different brain regions and on N-methyl-D-aspartate (NMDA) receptor mRNA expression in the hippocampus of rats. On the basis of these observations, we explored possible mechanisms by which lead exposure leads to impaired learning and memorizing abilities in children. Methods: A series of rat animal models exposed to low levels of lead during the developing period was established (drinking water containing 0.025%, 0.05% and 0.075% lead acetate). NOS activities in the hippocampus, the cerebral cortex, the cerebellum and the brain stem were determined with fluorescence measurement and levels of mRNA expression of the NMDA receptor 2A (NR2A) subunit and NMDA receptor 2B (NR2B) subunit in the rat hippocampus were measured with Retro-translation (RT-PCR). Results: There were no differences in the body weight of rat pups between any of the groups at any given time (P>0.05). The blood lead level of Pb-exposed rat pups showed a systematic pattern of change: at 14 d of age, it was lower than that at 7 d of age, then rising to the peak level at 21 d and finally falling to lower levels at 28 d. The hippocampal NOS activities of lead-exposed groups were all lower than that of the control group on the 21 st and 28th day (P<0.01). NOS activities in the cerebellum of lead-exposed groups were all lower than that of the control group on the 21 st and 28th day (P<0.001) and the NOS activity of the 0.025% group was significantly lower than that of the 0.05% and 0.075% groups on the 28th day (P<0.05).NOS activity in the cerebral cortex of the 0.075% group was significantly lower than that of the control, 0.025% and 0.05% groups on the four day spans (P<0.001). There was no significant difference of NOS activity in the brain stem between any lead-exposed group and the control group on the four day spans. In the 0.05% and the 0.075% groups, the level of NR2A mRNA expression was higher than that in the control group at 7 d and 14 展开更多
Objective To estimate the detrimental effects of shortwave exposure on rat hippocampal structure and function and explore the underlying mechanisms. Methods One hundred Wistar rats were randomly divided into four grou...Objective To estimate the detrimental effects of shortwave exposure on rat hippocampal structure and function and explore the underlying mechanisms. Methods One hundred Wistar rats were randomly divided into four groups(25 rats per group) and exposed to 27 MHz continuous shortwave at a power density of 5, 10, or 30 m W/cm^2 for 6 min once only or underwent sham exposure for the control. The spatial learning and memory, electroencephalogram(EEG), hippocampal structure and Nissl bodies were analysed. Furthermore, the expressions of N-methyl-D-aspartate receptor(NMDAR) subunits(NR1, NR2 A, and NR2 B), c AMP responsive element-binding protein(CREB) and phosphorylated CREB(p-CREB) in hippocampal tissue were analysed on 1, 7, and 14 days after exposure. Results The rats in the 10 and 30 m W/cm^2 groups had poor learning and memory, disrupted EEG oscillations, and injured hippocampal structures, including hippocampal neurons degeneration, mitochondria cavitation and blood capillaries swelling. The Nissl body content was also reduced in the exposure groups. Moreover, the hippocampal tissue in the 30 m W/cm^2 group had increased expressions of NR2 A and NR2 B and decreased levels of CREB and p-CREB. Conclusion Shortwave exposure(27 MHz, with an average power density of 10 and 30 m W/cm^2) impaired rats' spatial learning and memory and caused a series of dose-dependent pathophysiological changes. Moreover, NMDAR-related CREB pathway suppression might be involved in shortwave-induced structural and functional impairments in the rat hippocampus.展开更多
基金supported by the National Natural Science Foundation of China,No.81260295the Natural Science Foundation of Jiangxi Province of China,No.20132BAB205063
文摘Electrical stimulation of the median nerve is a noninvasive technique that facilitates awakening from coma. In rats with traumatic brain injury-induced coma, median nerve stimulation markedly enhances prefrontal cortex expression of orexin-A and its receptor, orexin receptor 1. To further understand the mechanism underlying wakefulness mediated by electrical stimulation of the median nerve, we evaluated its effects on the expression of the N-methyl-D-aspartate receptor subunit NR1 in the prefrontal cortex in rat models of traumatic brain injury-induced coma, using immunohistochemistry and western blot assays. In rats with traumatic brain injury, NR1 expression increased with time after injury. Rats that underwent electrical stimulation of the median nerve（30 Hz, 0.5 ms, 1.0 m A for 15 minutes） showed elevated NR1 expression and greater recovery of consciousness than those without stimulation. These effects were reduced by intracerebroventricular injection of the orexin receptor 1 antagonist SB334867. Our results indicate that electrical stimulation of the median nerve promotes recovery from traumatic brain injury-induced coma by increasing prefrontal cortex NR1 expression via an orexin-A-mediated pathway.
基金Project (No. 021103009) supported by the Science and Technology Bureau of Zhejiang Province, China
文摘Objective: To investigate effects of developmental lead exposure on nitric oxide synthase (NOS) activity in different brain regions and on N-methyl-D-aspartate (NMDA) receptor mRNA expression in the hippocampus of rats. On the basis of these observations, we explored possible mechanisms by which lead exposure leads to impaired learning and memorizing abilities in children. Methods: A series of rat animal models exposed to low levels of lead during the developing period was established (drinking water containing 0.025%, 0.05% and 0.075% lead acetate). NOS activities in the hippocampus, the cerebral cortex, the cerebellum and the brain stem were determined with fluorescence measurement and levels of mRNA expression of the NMDA receptor 2A (NR2A) subunit and NMDA receptor 2B (NR2B) subunit in the rat hippocampus were measured with Retro-translation (RT-PCR). Results: There were no differences in the body weight of rat pups between any of the groups at any given time (P>0.05). The blood lead level of Pb-exposed rat pups showed a systematic pattern of change: at 14 d of age, it was lower than that at 7 d of age, then rising to the peak level at 21 d and finally falling to lower levels at 28 d. The hippocampal NOS activities of lead-exposed groups were all lower than that of the control group on the 21 st and 28th day (P<0.01). NOS activities in the cerebellum of lead-exposed groups were all lower than that of the control group on the 21 st and 28th day (P<0.001) and the NOS activity of the 0.025% group was significantly lower than that of the 0.05% and 0.075% groups on the 28th day (P<0.05).NOS activity in the cerebral cortex of the 0.075% group was significantly lower than that of the control, 0.025% and 0.05% groups on the four day spans (P<0.001). There was no significant difference of NOS activity in the brain stem between any lead-exposed group and the control group on the four day spans. In the 0.05% and the 0.075% groups, the level of NR2A mRNA expression was higher than that in the control group at 7 d and 14
基金supported by the National Natural Science Fund [No.31570847]the fund organization had no role in the design or conduct of this research
文摘Objective To estimate the detrimental effects of shortwave exposure on rat hippocampal structure and function and explore the underlying mechanisms. Methods One hundred Wistar rats were randomly divided into four groups(25 rats per group) and exposed to 27 MHz continuous shortwave at a power density of 5, 10, or 30 m W/cm^2 for 6 min once only or underwent sham exposure for the control. The spatial learning and memory, electroencephalogram(EEG), hippocampal structure and Nissl bodies were analysed. Furthermore, the expressions of N-methyl-D-aspartate receptor(NMDAR) subunits(NR1, NR2 A, and NR2 B), c AMP responsive element-binding protein(CREB) and phosphorylated CREB(p-CREB) in hippocampal tissue were analysed on 1, 7, and 14 days after exposure. Results The rats in the 10 and 30 m W/cm^2 groups had poor learning and memory, disrupted EEG oscillations, and injured hippocampal structures, including hippocampal neurons degeneration, mitochondria cavitation and blood capillaries swelling. The Nissl body content was also reduced in the exposure groups. Moreover, the hippocampal tissue in the 30 m W/cm^2 group had increased expressions of NR2 A and NR2 B and decreased levels of CREB and p-CREB. Conclusion Shortwave exposure(27 MHz, with an average power density of 10 and 30 m W/cm^2) impaired rats' spatial learning and memory and caused a series of dose-dependent pathophysiological changes. Moreover, NMDAR-related CREB pathway suppression might be involved in shortwave-induced structural and functional impairments in the rat hippocampus.
