GABA及其受体拮抗剂对脑缺血大鼠海马CA3区诱发电位的影响  

Effects of GABA on synaptic transmission of hippocampus CA3 neurons after brain ischemia in rats

作　　者：徐旭林[1] 胡环忠[2] 孙铁[1] 余尚斌[3] 欧阳昌汉[1] 曲玲[1] 吕青[1] 郭莲军[1] 

机构地区：[1]华中科技大学同济医学院药理教研室,湖北武汉430030 [2]华中科技大学同济医学院生理教研室,湖北武汉430030 [3]华中科技大学同济医学院机能学中心实验室,湖北武汉430030

出　　处：《中国药学杂志》2004年第9期666-669,共4页Chinese Pharmaceutical Journal

基　　金：国家自然基金资助课题(30171082)

摘　　要：目的 探讨γ-aminobutyric acid(GABA)及其受体拮抗剂对正常及脑缺血大鼠海马CA3区神经元突触传递功能的影响。方法在体记录正常大鼠海马CA3区诱发的群峰电(population spike,PS);结扎大鼠双侧颈总动脉,造成急性不完全性全脑缺血,观察PS幅度变化;采用局部微量给药,观察药物对PS幅度的影响。结果①GABA 100,200 mmol·L-1局部注入后,PS的幅度显著降低.bicuculline 1 mmol·L-1能明显拮抗GABA200 mmol·L-1对PS幅度降低的作用。②Glu 10 mmol·L-1注入后,PS的幅度较注药前显著增加。而Glu 50 mmol·L-1注入后,PS的幅度则较注药前显著降低。③GABA 200 mmol·L-1能显著降低Glu10 mmol·L-1所导致的PS幅度增加,并能减弱Glu 50 mmol·L-1对PS幅度的降低作用。④急性不完全性全脑缺血(结扎双侧颈总动脉)后,PS的幅度显著降低。GABA 200 mmol·L-1能减轻脑缺血所致的PS幅度的降低。结论 GABA对正常大鼠海马神经元突触传递的兴奋性具有一定抑制作用。并能明显改善较大剂量谷氨酸和急性脑缺血对海马CA3区神经元突触传递的影响。OBJECTIVE: To observe the effects of γ-GABA on evoked potential (population spike, PS) in the hippocampus CA3 region after brain ischemia. METHODS: Transient incomplete global brain ischemia was caused by occluding both carotid arteries. Intracellular recording was used to study the amplitude of PS of hippocampus CA3 area in vivo. RESULTS: The animal received a GABA intra-hippocampal infusion of 100 mmol&middotL-1 and 200 mmol&middotL-1, respectively. Both GABA-treated groups had a dose-dependent decrease of the PS amplitude at all measured time points (0, 10, 20, 30, 40, 50, 60 min). Bicuculline 1 mmol&middotL-1 antagonised the action of 200 mmol&middotL-1 GABA. Glu 10 mmol&middot L -1 increased PS amplitude. But Glu 50 mmol&middotL-1 significantly decreased the amplitude of PS. GABA 200 mmol&middotL-1 suppressed both the effects of Glu 10 mmol&middotL-1 and Glu 50 mmol&middotL-1. After both carotid arteries was occluded to cause incomplete global brain ischemia, the amplitude of PS decreased significantly. GABA 200 mmol&middotL-1 attenuated the depression effect of ischemia. CONCLUSION: The results suggest that GABA plays an important regulative role in the changes of synaptic transmission induced by EAA and brain ischemia in rata.

关 键 词：脑缺血 诱发电位 海马CA3区 GABA 

分 类 号：R965[医药卫生—药理学]