Status epilepticus was induced via intraperitoneal injection of lithium-pilocarpine.The inhibitory effects of propofol on status epilepticus in rats were judged based on observation of behavior,electroencephalography ...Status epilepticus was induced via intraperitoneal injection of lithium-pilocarpine.The inhibitory effects of propofol on status epilepticus in rats were judged based on observation of behavior,electroencephalography and 24-hour survival rate.Propofol（12.5-100 mg/kg） improved status epilepticus in a dose-dependent manner,and significantly reduced the number of deaths within 24 hours of lithium-pilocarpine injection.Western blot results showed that,24 hours after induction of status epilepticus,the levels of N-methyl-D-aspartate receptor 2A and 2B subunits were significantly increased in rat cerebral cortex and hippocampus.Propofol at 50 mg/kg significantly suppressed the increase in N-methyl-D-aspartate receptor 2B subunit levels,but not the increase in N-methyl-D-aspartate receptor 2A subunit levels.The results suggest that propofol can effectively inhibit status epilepticus induced by lithium-pilocarpine.This effect may be associated with downregulation of N-methyl-D-aspartate receptor 2B subunit expression after seizures.展开更多
Objective To study the effect of chronic noise exposure on expression of N-methyI-D-aspartic acid receptor 2B （NR2B） and tau phosphorylation in hippocampus of rats. Methods Twenty-four male SD rats were divided in c...Objective To study the effect of chronic noise exposure on expression of N-methyI-D-aspartic acid receptor 2B （NR2B） and tau phosphorylation in hippocampus of rats. Methods Twenty-four male SD rats were divided in control group and chronic noise exposure group. NR2B expression and tau phosphorylation in hippocampus of rats were detected after chronic noise exposure （100 dB SPL white noise, 4 h/dx30d） and their mechanisms underlying neuronal apoptosis in hippocampus of rats with TUNEL staining. Results The NR2B expression decreased significantly after chronic noise exposure which resulted in tau hyperphosphorylation and neural apoptosis in hippocampus of rats. Immunohistochemistry showed that the tau hyperphosphorylation was most prominent in dentate gyrus （DG） and CA1 region of rat hippocampus. Conclusion The abnormality of neurotransmitter system, especially Glu and NR2B containing NMDA receptor, and tau hyperphosphorylation in hippocampus of rats, may play a role in chronic noise-induced neural apoptosis and cognition impairment.展开更多
Spinal dorsal horn N-Methyl-D-aspartic acid receptor 2B （NR2B） overexpression plays an important role in the production and maintenance of neuropathic pain. Because small interfering RNA （siRNA） can inhibit NR2B e...Spinal dorsal horn N-Methyl-D-aspartic acid receptor 2B （NR2B） overexpression plays an important role in the production and maintenance of neuropathic pain. Because small interfering RNA （siRNA） can inhibit NR2B expression, siRNA may provide a novel approach to treat neuropathic pain and possibly nerve injury. However, an efficient and safe vector for NR2B siRNA has not been discovered. This study shows that a water soluble lipopolymer （WSLP） comprised of low molecular weight polyethyleneimine （PEI） and cholesterol can deliver siRNA targeting NR2B for the treatment of neuropathic pain. Results show that intrathecal injection of WSLP/siRNA complexes for 3 days inhibit NR2B gene expression with reductions in mRNA and protein levels by 59% and 54%, respectively, compared with control rats （P 〈 0.01）. Injection of WSLP complexed with scrambled siRNA, or PEI with siRNA did not show this inhibitory effect. Moreover, injection of WSLP/siRNA complexes significantly relieved neuropathic pain at 3, 7, 12, and 21 days, while injection of WSLP with scrambled siRNA or PEI with siRNA did not. These results demonstrate that WSLP can efficiently deliver siRNA targeting NR2B in vivo and relieve neuropathic pain.展开更多
The γ-aminobutyric acid neurotransmitter in the spinal cord dorsal horn plays an important role in pain modulation through primary afferent-mediated presynaptic inhibition. The weakening of γ-aminobutyric acid-media...The γ-aminobutyric acid neurotransmitter in the spinal cord dorsal horn plays an important role in pain modulation through primary afferent-mediated presynaptic inhibition. The weakening of γ-aminobutyric acid-mediated presynaptic inhibition may be an important cause of neuropathic pain. γ-aminobutyric acid-mediated presynaptic inhibition is related to the current strength of γ-aminobutyric acid A receptor activation. In view of this, the whole-cell patch-clamp technique was used here to record the change in muscimol activated current of dorsal root ganglion neurons in a chronic constriction injury model. Results found that damage in rat dorsal root ganglion neurons following application of muscimol caused concentration-dependent activation of current, and compared with the sham group, its current strength and γ-aminobutyric acid A receptor protein expression decreased. Immunofluorescence revealed that γ-aminobutyric acid type A receptor α2 subunit protein expression decreased and was most obvious at 12 and 15 days after modeling. Our experimental findings confirmed that the y-aminobutyric acid type A receptor α2 subunit in the chronic constriction injury model rat dorsal root ganglion was downregulated, which may be one of the reasons for the reduction of injury in dorsal root ganglion neurons following muscimol-activated currents.展开更多
BACKGROUND： Studies have demonstrated that in vitro cultured cortical neurons from embryonic rats can produce spontaneous recurrent epileptiform discharges following transient Mg^2＋-free extracellular solution cultu...BACKGROUND： Studies have demonstrated that in vitro cultured cortical neurons from embryonic rats can produce spontaneous recurrent epileptiform discharges following transient Mg^2＋-free extracellular solution culture. OBJECTIVE： To explore gammaminobutyric acid A receptor （GABAAR）γ 2 subunit expression following Mg^2＋-free-induced seizures in cultured developing neurons. DESIGN, TIME AND SETTING： Cellular and molecular biology. The in vitro experiment was performed at the Department of Pediatrics, Second Xiangya Hospital of Central Southern University between January 2007 and February 2008. MATERIALS： Cortical neurons of Wistar rats on gestational days 16-17 were used. Normal extracellular solution （pH 7.3） consisted of NaCl 145 mmol/L, KCl 2.5 mmol/L, HEPES l0 mmol/L, MgC12 1 mmol/L, CaC12 2 mmol/L, glucose 10 mmol/L, and glycine 0.01 mmol/L. In addition, there was no MgCl2 in the Mg^2＋-free extracellular solution. METHODS： Cortical neurons cultured for 6 days were exposed to normal extracellular solution （control group） and Mg^2＋-free media （Mg^2＋-free group） respectively for 3 hours, followed by continuous culture in DMEM solution. MAIN OUTCOME MEASURES： On days 1, 7 and 12 after Mg^2＋-free treatment, real-time RT-PCR, immunochemistry, and flow cytometry were used to detect GABAAR 3/2 subunit expression. RESULTS： Compared with the control group, GABAAR γ-positive cells decreased significantly on days 1 and 7 after Mg^2＋-free treatment （P 〈 0.01）, but significantly increased on day 12 （P 〈 0.01 ）. GABAAR γ2 subunit mRNA expression decreased significantly at 7 days Mg^2＋-free treatment when measured by real-time RT-PCR compared with the control group （P 〈 0.05）. CONCLUSION： GABAAR γ2 subunit expression is modified following Mg-free-induced seizures in cultured developing neurons. This indicates the possibility that abnormal GABAA receptor expression might play an important role in development of neuronal injury.展开更多
In normal rat forebrain, the NR1/NR2A and NR1/NR2B dimmers are the main constitutional forms of NMDA receptors. The present study was carried out to determine the functional properties of the heteromeric NMDA receptor...In normal rat forebrain, the NR1/NR2A and NR1/NR2B dimmers are the main constitutional forms of NMDA receptors. The present study was carried out to determine the functional properties of the heteromeric NMDA receptor subunits and their inhibition by bis(7)-tacrine (B7T). Rat NR1, NR2A and NR2B cDNAs were transfected into human embryonic kidney 293 cells (HEK-293).The inhibition of NMDA-activated currents by B7T was detected in HEK-293 cell expressing NR1/NR2A or NR1/NR2B receptors by using whole-cell patch-clamp techniques. The results showed that in HEK-293 cells expressing NR1/NR2A receptor, 1μmol/L B7T inhibited 30μmol/L NMDA- and 1000μmol/L NMDA-activated steady-state currents by 46% and 40%, respectively (P>0.05; n=5), suggesting that the inhibition of B7T on NR1/NR2A receptor doesn’t depend on NMDA concentration, which is consistent with a non-competitive mechanism of inhibition. But for the NR1/NR2B receptor, 1μmol/L B7T inhibited 30μmol/L NMDA- and 1000 μmol/L NMDA-activated steady-state currents by 61% and 13%, re-spectively (P<0.05; n=6), showing that B7T appears to be competitive with NMDA. In addition, simultaneous application of 1μmol/L B7T and 1000μmol/L NMDA produced a moderate inhibition of peak NMDA-activated current, followed by a gradual decline of the current to a steady state. However, the gradual onset of inhibition produced by B7T applied simultaneously with NMDA was eliminated when B7T was given 5s before NMDA. These results suggested that B7T inhibition of NMDA current mediated by NR1/NR2B receptor was slow onset, and it did not depend on the presence of the agonist. With holding potentials ranging from -50 to +50 mV, the B7T inhibition rate of NMDA currents didn’t change significantly, and neither did the reversal potential. We are led to conclude that the NR1/NR2B recombinant receptor can serve as a very useful model for studying the molecular mechanism of NMDA receptor inhibition by B7T.展开更多
Background Cocaine addiction may involve complex neuroadaptations, including many changes of genes expression. Dopamine D3 receptors play an important role in cocaine addiction; however, its role in cocaine induced ge...Background Cocaine addiction may involve complex neuroadaptations, including many changes of genes expression. Dopamine D3 receptors play an important role in cocaine addiction; however, its role in cocaine induced gene expression change is poorly understood. To identify the changes in gene expression induced by repeated cocaine exposure through D3 dopamine receptors, we compared the expression of four molecules： Janus kinase 2 （Jak2）, g-aminobutanoic acid receptor subunit alpha 1 （GABAAα1）, glutamate receptor AMPA3 alpha 3 （GluR 3） and stromal cell derived factor 1 （SDF1）. These four have been implicated in mediating the actions of cocaine in the nucleus accumbens （NAc） and caudoputamen （CPu） in mice after acute and repeated cocaine exposure. Methods For the acute and repeated injections, the mice were divided into four groups： 30 mg/kg cocaine, nafadotride 0.5 mg/kg ＋ cocaine 30 mg/kg, nafadotride 0.5 mg/kg, and saline as the basal group. The expression of Jak2, GABAAα1, GluR 3 and SDF1 were assayed by Western blot, quantitative real-time RT-PCR and immunohistochemistry. Results Twenty-four hours after seven consecutive days of repeated cocaine exposure, the expression of GABAAα1 decreased in cocaine group compared with basal line and further decreased in the cocaine ＋ nafadotride group and remained at basal level in the nafadotride group. Similarly, the Jak2 expression decreased in cocaine group compared with base line. However, the levels of Jak2 increased in cocaine ＋ nafadotride group compared with cocaine group, while remained at basal level in nafadotride group. Conclusions GABAAα1 and Jak2 may be involved in chronic cocaine induced neuroadaptations. D3 dopamine receptors play an important role in the expression of these genes.展开更多
Tetrandrine is one of the major active ingredients in Menispermaceae Stephania tetrandra S.Moore,and has specific therapeutic effects in ischemic cerebrovascular disease.Its use in vascular dementia has not been studi...Tetrandrine is one of the major active ingredients in Menispermaceae Stephania tetrandra S.Moore,and has specific therapeutic effects in ischemic cerebrovascular disease.Its use in vascular dementia has not been studied fully.Here,we investigated whether tetrandrine would improve behavioral and cellular impairments in a two-vessel occlusion rat model of chronic vascular dementia.Eight weeks after model establishment,rats were injected intraperitoneally with 10 or 30 mg/kg tetrandrine every other day for 4 weeks.Behavioral assessment in the Morris water maze showed that model rats had longer escape latencies in training trials,and spent less time swimming in the target quadrant in probe trials,than sham-operated rats.However,rats that had received tetrandrine showed shorter escape latencies and longer target quadrant swimming time than untreated model rats.Hematoxylin-eosin and Nissl staining revealed less neuronal necrosis and pathological damage,and more living cells,in the hippocampus of rats treated with tetrandrine than in untreated model rats.Western blot assay showed that interleukin-1β expression,and phosphorylation of the N-methyl-D-aspartate 2B receptor at tyrosine 1472,were lower in model rats that received tetrandrine than in those that did not.The present findings suggest that tetrandrine may be neuroprotective in chronic vascular dementia by reducing interleukin-1β expression,N-methyl-D-aspartate receptor 2B phosphorylation at tyrosine 1472,and neuronal necrosis.展开更多
Bushen Tiansui decoction is composed of six traditional Chinese medicines：Herba Epimedii,Radix Polygoni multiflori,Plastrum testudinis,Fossilia Ossis Mastodi,Radix Polygalae,and Rhizoma Acorus tatarinowii.Because Bus...Bushen Tiansui decoction is composed of six traditional Chinese medicines：Herba Epimedii,Radix Polygoni multiflori,Plastrum testudinis,Fossilia Ossis Mastodi,Radix Polygalae,and Rhizoma Acorus tatarinowii.Because Bushen Tiansui decoction is effective against amyloid beta（Aβ） toxicity,we hypothesized that it would reduce hippocampal synaptic damage and improve cognitive function in Alzheimer＇s disease.To test this hypothesis,we used a previously established animal model of Alzheimer＇s disease,that is,microinjection of aggregated Aβ25–35 into the bilateral brain ventricles of Sprague-Dawley rats.We found that long-term（28 days） oral administration of Bushen Tiansui decoction（0.563,1.688,and 3.375 g/m L;4 m L/day） prevented synaptic loss in the hippocampus and increased the expression levels of synaptic proteins,including postsynaptic density protein 95,the N-methyl-D-aspartate receptor 2 B subunit,and Shank1.These results suggested that Bushen Tiansui decoction can protect synapses by maintaining the expression of these synaptic proteins.Bushen Tiansui decoction also ameliorated measures reflecting spatial learning and memory deficits that were observed in the Morris water maze（i.e.,increased the number of platform crossings and the amount of time spent in the target quadrant and decreased escape latency） following intraventricular injections of aggregated Aβ25–35 compared with those measures in untreated Aβ_（25–35）-injected rats.Overall,these results provided evidence that further studies on the prevention and treatment of dementia with this traditional Chinese medicine are warranted.展开更多
遗传性癫痫伴热性惊厥附加症(Genetic epilepsy with febrile seizures plus,GEFS+)是一种新型遗传性癫痫综合征,具有明显的家族遗传史。临床表现常为热性惊厥,其次是热性惊厥附加症及伴或不伴失神发作、局灶性发作及全身强直-阵挛性发...遗传性癫痫伴热性惊厥附加症(Genetic epilepsy with febrile seizures plus,GEFS+)是一种新型遗传性癫痫综合征,具有明显的家族遗传史。临床表现常为热性惊厥,其次是热性惊厥附加症及伴或不伴失神发作、局灶性发作及全身强直-阵挛性发作等。利用聚合酶连反应、外显子测序、单核苷酸多态性分析等技术研究发现,其发生主要与γ-氨基丁酸A型受体的γ2亚基(Gamma aminobutyric acid type A receptor gamma 2 subunit,GABRG2)基因突变有关,但其发病机制仍未阐明。GABRG2突变类型主要有错义突变、无义突变、移码突变、点突变及剪接体位点突变等。其所有类型的突变均会降低细胞膜上相关离子通道的功能,但引起功能障碍的程度和机制并不相同,这可能是致痫的主要机制。文章将重点综述近年来研究发现的该基因突变类型与GEFS+相关性,为辅助临床精确诊断、抗癫痫治疗策略及新药开发具有重要意义。展开更多
Stroke and Alzheimer's disease are common neurological disorders and often occur in the same individuals.The comorbidity of the two neurological disorders represents a grave health threat to older populations.This...Stroke and Alzheimer's disease are common neurological disorders and often occur in the same individuals.The comorbidity of the two neurological disorders represents a grave health threat to older populations.This review presents a brief background of the development of novel concepts and their clinical potentials.The activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca^(2+)influx is critical for neuronal function.An ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca^(2+)mainly via N-methyl-D-aspartate receptors,particularly of those at the extrasynaptic site.This Ca^(2+)-evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute excitotoxicity.Furthermore,mild but sustained Ca^(2+)increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic,but gradually set off deteriorating Ca^(2+)-dependent signals and neuronal cell loss mostly because of activation of programmed cell death pathways.Based on the Ca^(2+)hypothesis of Alzheimer's disease and recent advances,this Ca^(2+)-activated“silent”degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic neuropathogenesis.The N-methyl-D-aspartate receptor subunit GluN3A,primarily at the extrasynaptic site,serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic excitotoxicity.Ischemic stroke and Alzheimer's disease,therefore,share an N-methyl-D-aspartate receptor-and Ca^(2+)-mediated mechanism,although with much different time courses.It is thus proposed that early interventions to control Ca^(2+)homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related dementia.This early treatment simultaneously serves as a preconditioning therapy against ischemic stroke that often attacks the same individuals during abnormal aging.展开更多
OBJECTIVE:To evaluate the therapeutic efficacy and the influence on cerebral blood supply of waggle needling Yanglingquan(GB34) on spastic paresis(SP) rats after middle cerebral artery occlusion(MCAO) induced and inve...OBJECTIVE:To evaluate the therapeutic efficacy and the influence on cerebral blood supply of waggle needling Yanglingquan(GB34) on spastic paresis(SP) rats after middle cerebral artery occlusion(MCAO) induced and investigate its mechanism of relieving neurobehavior deficiency.METHODS:SP rat model was produced by permanent MCAO.Rats were divided into five groups:blank control group(Control),sham operation group(Sham),model group(Model),waggle needling group(WN) and perpendicular needling group(PN).SP rats were treated with acupuncture from day 3 after MCAO,once a day for 6 d.The modified neurological severity score(m NSS) and modified Ashworth scale(MAS) were conducted on days 0,1,3,5,7 and 9.Cerebral blood flow(CBF) in ischemic cortex was measured by laser speckle imaging 5 min pre ischemia,5 min post ischemia,and after intervention on day 9.All rats were sacrificed at day 9 and the protein and m RNA expressions of γ2 subunit of the γ-aminobutyric acid receptor A(GABAAγ2) and K+-Cl-cotransporter 2(KCC2) in the ischemic cortex and lumber enlargement was measured by Western blotting and real-time quantitative polymerase chain reaction.RESULTS:Both Control and Sham groups showed no changes in m NSS and MAS scores and in the regional CBF.Compared with Model group,both WN and PN treatments significantly ameliorated neurological deficit(P < 0.01),decreased muscle tone(P < 0.05),and enhanced CBF(P < 0.001) in SP rats;moreover,WN showed superior effects than PN(P < 0.001).In line with the improvement in neurobehavior,acupuncture interventions up-regulated the expressions of GABAAγ2 and KCC2 in the ischemic cortex as well as lumber enlargement(P < 0.01) in SP rats,and those changes were more obvious in WN(P < 0.05).CONCLUSIONS:Acupuncture at Yanglingquan(GB34) enhanced cerebral blood flow and ameliorated SP in permanent MCAO rats,while waggle needling was superior to regular perpendicular needling.Waggle needling Yanglingquan(GB34) would be a potential complementary therapy for SP.展开更多
基金supported by National Natural Science Foundation of China,No. 30500482
文摘Status epilepticus was induced via intraperitoneal injection of lithium-pilocarpine.The inhibitory effects of propofol on status epilepticus in rats were judged based on observation of behavior,electroencephalography and 24-hour survival rate.Propofol（12.5-100 mg/kg） improved status epilepticus in a dose-dependent manner,and significantly reduced the number of deaths within 24 hours of lithium-pilocarpine injection.Western blot results showed that,24 hours after induction of status epilepticus,the levels of N-methyl-D-aspartate receptor 2A and 2B subunits were significantly increased in rat cerebral cortex and hippocampus.Propofol at 50 mg/kg significantly suppressed the increase in N-methyl-D-aspartate receptor 2B subunit levels,but not the increase in N-methyl-D-aspartate receptor 2A subunit levels.The results suggest that propofol can effectively inhibit status epilepticus induced by lithium-pilocarpine.This effect may be associated with downregulation of N-methyl-D-aspartate receptor 2B subunit expression after seizures.
基金supported by a grant from the National Natural Science Foundation of China (No. 81001237)
文摘Objective To study the effect of chronic noise exposure on expression of N-methyI-D-aspartic acid receptor 2B （NR2B） and tau phosphorylation in hippocampus of rats. Methods Twenty-four male SD rats were divided in control group and chronic noise exposure group. NR2B expression and tau phosphorylation in hippocampus of rats were detected after chronic noise exposure （100 dB SPL white noise, 4 h/dx30d） and their mechanisms underlying neuronal apoptosis in hippocampus of rats with TUNEL staining. Results The NR2B expression decreased significantly after chronic noise exposure which resulted in tau hyperphosphorylation and neural apoptosis in hippocampus of rats. Immunohistochemistry showed that the tau hyperphosphorylation was most prominent in dentate gyrus （DG） and CA1 region of rat hippocampus. Conclusion The abnormality of neurotransmitter system, especially Glu and NR2B containing NMDA receptor, and tau hyperphosphorylation in hippocampus of rats, may play a role in chronic noise-induced neural apoptosis and cognition impairment.
基金the Natural Science Foundation of Guangdong Province,No.07000059the Science and Technology Development Program of Guangzhou,No.2010Y1-C301the Science and Technology Development Program of Guangdong Province,No.2010B031600123
文摘Spinal dorsal horn N-Methyl-D-aspartic acid receptor 2B （NR2B） overexpression plays an important role in the production and maintenance of neuropathic pain. Because small interfering RNA （siRNA） can inhibit NR2B expression, siRNA may provide a novel approach to treat neuropathic pain and possibly nerve injury. However, an efficient and safe vector for NR2B siRNA has not been discovered. This study shows that a water soluble lipopolymer （WSLP） comprised of low molecular weight polyethyleneimine （PEI） and cholesterol can deliver siRNA targeting NR2B for the treatment of neuropathic pain. Results show that intrathecal injection of WSLP/siRNA complexes for 3 days inhibit NR2B gene expression with reductions in mRNA and protein levels by 59% and 54%, respectively, compared with control rats （P 〈 0.01）. Injection of WSLP complexed with scrambled siRNA, or PEI with siRNA did not show this inhibitory effect. Moreover, injection of WSLP/siRNA complexes significantly relieved neuropathic pain at 3, 7, 12, and 21 days, while injection of WSLP with scrambled siRNA or PEI with siRNA did not. These results demonstrate that WSLP can efficiently deliver siRNA targeting NR2B in vivo and relieve neuropathic pain.
基金supported by the Youth Science and Technology Innovation Special Foundation of Xinjiang Production and Construction Corps, China, No. 2010JC33
文摘The γ-aminobutyric acid neurotransmitter in the spinal cord dorsal horn plays an important role in pain modulation through primary afferent-mediated presynaptic inhibition. The weakening of γ-aminobutyric acid-mediated presynaptic inhibition may be an important cause of neuropathic pain. γ-aminobutyric acid-mediated presynaptic inhibition is related to the current strength of γ-aminobutyric acid A receptor activation. In view of this, the whole-cell patch-clamp technique was used here to record the change in muscimol activated current of dorsal root ganglion neurons in a chronic constriction injury model. Results found that damage in rat dorsal root ganglion neurons following application of muscimol caused concentration-dependent activation of current, and compared with the sham group, its current strength and γ-aminobutyric acid A receptor protein expression decreased. Immunofluorescence revealed that γ-aminobutyric acid type A receptor α2 subunit protein expression decreased and was most obvious at 12 and 15 days after modeling. Our experimental findings confirmed that the y-aminobutyric acid type A receptor α2 subunit in the chronic constriction injury model rat dorsal root ganglion was downregulated, which may be one of the reasons for the reduction of injury in dorsal root ganglion neurons following muscimol-activated currents.
基金the National Natural Science Foundation of China,No.30400483
文摘BACKGROUND： Studies have demonstrated that in vitro cultured cortical neurons from embryonic rats can produce spontaneous recurrent epileptiform discharges following transient Mg^2＋-free extracellular solution culture. OBJECTIVE： To explore gammaminobutyric acid A receptor （GABAAR）γ 2 subunit expression following Mg^2＋-free-induced seizures in cultured developing neurons. DESIGN, TIME AND SETTING： Cellular and molecular biology. The in vitro experiment was performed at the Department of Pediatrics, Second Xiangya Hospital of Central Southern University between January 2007 and February 2008. MATERIALS： Cortical neurons of Wistar rats on gestational days 16-17 were used. Normal extracellular solution （pH 7.3） consisted of NaCl 145 mmol/L, KCl 2.5 mmol/L, HEPES l0 mmol/L, MgC12 1 mmol/L, CaC12 2 mmol/L, glucose 10 mmol/L, and glycine 0.01 mmol/L. In addition, there was no MgCl2 in the Mg^2＋-free extracellular solution. METHODS： Cortical neurons cultured for 6 days were exposed to normal extracellular solution （control group） and Mg^2＋-free media （Mg^2＋-free group） respectively for 3 hours, followed by continuous culture in DMEM solution. MAIN OUTCOME MEASURES： On days 1, 7 and 12 after Mg^2＋-free treatment, real-time RT-PCR, immunochemistry, and flow cytometry were used to detect GABAAR 3/2 subunit expression. RESULTS： Compared with the control group, GABAAR γ-positive cells decreased significantly on days 1 and 7 after Mg^2＋-free treatment （P 〈 0.01）, but significantly increased on day 12 （P 〈 0.01 ）. GABAAR γ2 subunit mRNA expression decreased significantly at 7 days Mg^2＋-free treatment when measured by real-time RT-PCR compared with the control group （P 〈 0.05）. CONCLUSION： GABAAR γ2 subunit expression is modified following Mg-free-induced seizures in cultured developing neurons. This indicates the possibility that abnormal GABAA receptor expression might play an important role in development of neuronal injury.
基金supported by grants from the National Natural Science Foundation of China(No. 30970927)the Natural Science Foundation of Hubei Province, China(No.2008CDA053)the Wuhan Science and Technology Foundation(Nos.200970634270,201250499145-27 and 20115069-9189-23)
文摘In normal rat forebrain, the NR1/NR2A and NR1/NR2B dimmers are the main constitutional forms of NMDA receptors. The present study was carried out to determine the functional properties of the heteromeric NMDA receptor subunits and their inhibition by bis(7)-tacrine (B7T). Rat NR1, NR2A and NR2B cDNAs were transfected into human embryonic kidney 293 cells (HEK-293).The inhibition of NMDA-activated currents by B7T was detected in HEK-293 cell expressing NR1/NR2A or NR1/NR2B receptors by using whole-cell patch-clamp techniques. The results showed that in HEK-293 cells expressing NR1/NR2A receptor, 1μmol/L B7T inhibited 30μmol/L NMDA- and 1000μmol/L NMDA-activated steady-state currents by 46% and 40%, respectively (P>0.05; n=5), suggesting that the inhibition of B7T on NR1/NR2A receptor doesn’t depend on NMDA concentration, which is consistent with a non-competitive mechanism of inhibition. But for the NR1/NR2B receptor, 1μmol/L B7T inhibited 30μmol/L NMDA- and 1000 μmol/L NMDA-activated steady-state currents by 61% and 13%, re-spectively (P<0.05; n=6), showing that B7T appears to be competitive with NMDA. In addition, simultaneous application of 1μmol/L B7T and 1000μmol/L NMDA produced a moderate inhibition of peak NMDA-activated current, followed by a gradual decline of the current to a steady state. However, the gradual onset of inhibition produced by B7T applied simultaneously with NMDA was eliminated when B7T was given 5s before NMDA. These results suggested that B7T inhibition of NMDA current mediated by NR1/NR2B receptor was slow onset, and it did not depend on the presence of the agonist. With holding potentials ranging from -50 to +50 mV, the B7T inhibition rate of NMDA currents didn’t change significantly, and neither did the reversal potential. We are led to conclude that the NR1/NR2B recombinant receptor can serve as a very useful model for studying the molecular mechanism of NMDA receptor inhibition by B7T.
基金the grants from the Science Technology Research Project fo Guangdong Province[Mo.2005B50301010]the Natural Science Foundation of Guangdong Province[No 40204411 and.06024380]the Medical Science Research Foundation of Guangdong Province[No.A200537]
文摘Background Cocaine addiction may involve complex neuroadaptations, including many changes of genes expression. Dopamine D3 receptors play an important role in cocaine addiction; however, its role in cocaine induced gene expression change is poorly understood. To identify the changes in gene expression induced by repeated cocaine exposure through D3 dopamine receptors, we compared the expression of four molecules： Janus kinase 2 （Jak2）, g-aminobutanoic acid receptor subunit alpha 1 （GABAAα1）, glutamate receptor AMPA3 alpha 3 （GluR 3） and stromal cell derived factor 1 （SDF1）. These four have been implicated in mediating the actions of cocaine in the nucleus accumbens （NAc） and caudoputamen （CPu） in mice after acute and repeated cocaine exposure. Methods For the acute and repeated injections, the mice were divided into four groups： 30 mg/kg cocaine, nafadotride 0.5 mg/kg ＋ cocaine 30 mg/kg, nafadotride 0.5 mg/kg, and saline as the basal group. The expression of Jak2, GABAAα1, GluR 3 and SDF1 were assayed by Western blot, quantitative real-time RT-PCR and immunohistochemistry. Results Twenty-four hours after seven consecutive days of repeated cocaine exposure, the expression of GABAAα1 decreased in cocaine group compared with basal line and further decreased in the cocaine ＋ nafadotride group and remained at basal level in the nafadotride group. Similarly, the Jak2 expression decreased in cocaine group compared with base line. However, the levels of Jak2 increased in cocaine ＋ nafadotride group compared with cocaine group, while remained at basal level in nafadotride group. Conclusions GABAAα1 and Jak2 may be involved in chronic cocaine induced neuroadaptations. D3 dopamine receptors play an important role in the expression of these genes.
基金supported by the National Natural Science Foundation of China,No.81070886
文摘Tetrandrine is one of the major active ingredients in Menispermaceae Stephania tetrandra S.Moore,and has specific therapeutic effects in ischemic cerebrovascular disease.Its use in vascular dementia has not been studied fully.Here,we investigated whether tetrandrine would improve behavioral and cellular impairments in a two-vessel occlusion rat model of chronic vascular dementia.Eight weeks after model establishment,rats were injected intraperitoneally with 10 or 30 mg/kg tetrandrine every other day for 4 weeks.Behavioral assessment in the Morris water maze showed that model rats had longer escape latencies in training trials,and spent less time swimming in the target quadrant in probe trials,than sham-operated rats.However,rats that had received tetrandrine showed shorter escape latencies and longer target quadrant swimming time than untreated model rats.Hematoxylin-eosin and Nissl staining revealed less neuronal necrosis and pathological damage,and more living cells,in the hippocampus of rats treated with tetrandrine than in untreated model rats.Western blot assay showed that interleukin-1β expression,and phosphorylation of the N-methyl-D-aspartate 2B receptor at tyrosine 1472,were lower in model rats that received tetrandrine than in those that did not.The present findings suggest that tetrandrine may be neuroprotective in chronic vascular dementia by reducing interleukin-1β expression,N-methyl-D-aspartate receptor 2B phosphorylation at tyrosine 1472,and neuronal necrosis.
基金supported by the National Natural Science Foundation of China,No.81373705the Natural Science Foundation of Hunan Province in China,No.13JJ3030
文摘Bushen Tiansui decoction is composed of six traditional Chinese medicines：Herba Epimedii,Radix Polygoni multiflori,Plastrum testudinis,Fossilia Ossis Mastodi,Radix Polygalae,and Rhizoma Acorus tatarinowii.Because Bushen Tiansui decoction is effective against amyloid beta（Aβ） toxicity,we hypothesized that it would reduce hippocampal synaptic damage and improve cognitive function in Alzheimer＇s disease.To test this hypothesis,we used a previously established animal model of Alzheimer＇s disease,that is,microinjection of aggregated Aβ25–35 into the bilateral brain ventricles of Sprague-Dawley rats.We found that long-term（28 days） oral administration of Bushen Tiansui decoction（0.563,1.688,and 3.375 g/m L;4 m L/day） prevented synaptic loss in the hippocampus and increased the expression levels of synaptic proteins,including postsynaptic density protein 95,the N-methyl-D-aspartate receptor 2 B subunit,and Shank1.These results suggested that Bushen Tiansui decoction can protect synapses by maintaining the expression of these synaptic proteins.Bushen Tiansui decoction also ameliorated measures reflecting spatial learning and memory deficits that were observed in the Morris water maze（i.e.,increased the number of platform crossings and the amount of time spent in the target quadrant and decreased escape latency） following intraventricular injections of aggregated Aβ25–35 compared with those measures in untreated Aβ_（25–35）-injected rats.Overall,these results provided evidence that further studies on the prevention and treatment of dementia with this traditional Chinese medicine are warranted.
文摘遗传性癫痫伴热性惊厥附加症(Genetic epilepsy with febrile seizures plus,GEFS+)是一种新型遗传性癫痫综合征,具有明显的家族遗传史。临床表现常为热性惊厥,其次是热性惊厥附加症及伴或不伴失神发作、局灶性发作及全身强直-阵挛性发作等。利用聚合酶连反应、外显子测序、单核苷酸多态性分析等技术研究发现,其发生主要与γ-氨基丁酸A型受体的γ2亚基(Gamma aminobutyric acid type A receptor gamma 2 subunit,GABRG2)基因突变有关,但其发病机制仍未阐明。GABRG2突变类型主要有错义突变、无义突变、移码突变、点突变及剪接体位点突变等。其所有类型的突变均会降低细胞膜上相关离子通道的功能,但引起功能障碍的程度和机制并不相同,这可能是致痫的主要机制。文章将重点综述近年来研究发现的该基因突变类型与GEFS+相关性,为辅助临床精确诊断、抗癫痫治疗策略及新药开发具有重要意义。
基金supported by National Health Institute(NIH)grant NS099596(to LW and SPY),NS114221(to LW and SPY)Veterans Affair(VA)SPiRE grant RX003865(to SPY)+1 种基金supported by the O.Wayne Rollins Endowment Fund(to SPY)John E.Steinhaus Endowment Fund(to LW)。
文摘Stroke and Alzheimer's disease are common neurological disorders and often occur in the same individuals.The comorbidity of the two neurological disorders represents a grave health threat to older populations.This review presents a brief background of the development of novel concepts and their clinical potentials.The activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca^(2+)influx is critical for neuronal function.An ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca^(2+)mainly via N-methyl-D-aspartate receptors,particularly of those at the extrasynaptic site.This Ca^(2+)-evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute excitotoxicity.Furthermore,mild but sustained Ca^(2+)increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic,but gradually set off deteriorating Ca^(2+)-dependent signals and neuronal cell loss mostly because of activation of programmed cell death pathways.Based on the Ca^(2+)hypothesis of Alzheimer's disease and recent advances,this Ca^(2+)-activated“silent”degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic neuropathogenesis.The N-methyl-D-aspartate receptor subunit GluN3A,primarily at the extrasynaptic site,serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic excitotoxicity.Ischemic stroke and Alzheimer's disease,therefore,share an N-methyl-D-aspartate receptor-and Ca^(2+)-mediated mechanism,although with much different time courses.It is thus proposed that early interventions to control Ca^(2+)homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related dementia.This early treatment simultaneously serves as a preconditioning therapy against ischemic stroke that often attacks the same individuals during abnormal aging.
基金Supported by Scientific Research Development Fund Program of National Natural Science Foundation of China:Study on the Mechanism of Waggle Needling GB34 Relieving Spasticity in Poststroke Rats Based on KCC2-GABAA Receptor Pathway(No.81774417)the Fundamental Research Funds for the Central Universities of China:Research and Development of Physical Therapy Technology and Equipment for Regulation of Human Functional State(No.2020-JYB-ZDGG-062)。
文摘OBJECTIVE:To evaluate the therapeutic efficacy and the influence on cerebral blood supply of waggle needling Yanglingquan(GB34) on spastic paresis(SP) rats after middle cerebral artery occlusion(MCAO) induced and investigate its mechanism of relieving neurobehavior deficiency.METHODS:SP rat model was produced by permanent MCAO.Rats were divided into five groups:blank control group(Control),sham operation group(Sham),model group(Model),waggle needling group(WN) and perpendicular needling group(PN).SP rats were treated with acupuncture from day 3 after MCAO,once a day for 6 d.The modified neurological severity score(m NSS) and modified Ashworth scale(MAS) were conducted on days 0,1,3,5,7 and 9.Cerebral blood flow(CBF) in ischemic cortex was measured by laser speckle imaging 5 min pre ischemia,5 min post ischemia,and after intervention on day 9.All rats were sacrificed at day 9 and the protein and m RNA expressions of γ2 subunit of the γ-aminobutyric acid receptor A(GABAAγ2) and K+-Cl-cotransporter 2(KCC2) in the ischemic cortex and lumber enlargement was measured by Western blotting and real-time quantitative polymerase chain reaction.RESULTS:Both Control and Sham groups showed no changes in m NSS and MAS scores and in the regional CBF.Compared with Model group,both WN and PN treatments significantly ameliorated neurological deficit(P < 0.01),decreased muscle tone(P < 0.05),and enhanced CBF(P < 0.001) in SP rats;moreover,WN showed superior effects than PN(P < 0.001).In line with the improvement in neurobehavior,acupuncture interventions up-regulated the expressions of GABAAγ2 and KCC2 in the ischemic cortex as well as lumber enlargement(P < 0.01) in SP rats,and those changes were more obvious in WN(P < 0.05).CONCLUSIONS:Acupuncture at Yanglingquan(GB34) enhanced cerebral blood flow and ameliorated SP in permanent MCAO rats,while waggle needling was superior to regular perpendicular needling.Waggle needling Yanglingquan(GB34) would be a potential complementary therapy for SP.
