Changes of Expression of GABA_AR Induced by Acute Cerebral Ischemia in Rats

Objecive: To observe the expression of GABAAR and the dynamic regulation in the cortex of rats with focal cerebral ischemia in different phases and to investigate its significance in acute ischemia.Methods: Forty-eight male Wistar rats were randomly divided into 13 groups: The normal control,sham operation and ischemic operation group(subdivided into 6,12,24 hour and 3,7,14 days) by middle cerebral artery occlusion model.Brain specimens of the rats from each group were obtained for HE staining to observe the damage of neurons with light microscope and to judge the positive expression of neurons in immunohistochemistry technique,and then to determine the positive cell number expressed by GABAAR in each group with morphologic analysis system.Results: Compared with the normal control group and the sham operation group,the expression of GABAAR in each ischemia operation group was decreased 6h after ischemia and reached the bottom within 12 hours after ischemia.However,there was no significant difference between the normal control group and sham operation group.Conclusion: Acute cerebral ischemia can cause down-regulated expression of GABAAR and weaken its inhibitory action on glutamate excitotoxicity,which is accordant with the degree of cerebral ischemia injury,which suggests that GABAAR plays a role of nerve protection in cerebral ischemia injury and may slow down the progression of ischemic cerebrovascular disease,and that GABAAR,a major inhibitory neurotransmitter receptor of glutamate,undergoes some changes because of the physicochemical factors brought about by ischemia as it inhibits excitotoxicity through the action mediated by ligand gated chloride channel.