GABA_A Receptor α1 Protein Express In The Hippocampus And Cortex Of Rats In Status Epilepticus

ObjectivesTo investigate the expression levels of the GABAA receptorαl subunit in hippocampus and cortex after different duration of status epilepticusMethodsHealthy adult male Sprague-Dawley (SD) rats were 18, weight 250±20 g, were randomly divided into control group, SE1 h group and the SE2 h group. After establishing SE model of lithium-pilocarpine, the fresh brain tissue was sagittally sectioned into 300μm slices using a vibratome.3 brain slices of each mouse were incubated with sulfo-NHS-SS-biotin in order to label cell membrane proteins. The hippocampus and cortex were microdissected under a dissecting microscope. The protein of hippocampus and cortex were obtained after homogenized. The concentration of proteins were assayed using Bradford method.150μg of the homogenated cell protein of each mouse was incubated with neutravidin beads overnight, then centrifuged and kept the pellet which was cell membrane proteins. GAPDH was the marker of intracellar protein and sodium-potassium ATP enzyme was the internal control of cell membrane proteins and the whole cell proteins. The expression levels of GABAA receptorα1 subunit in cell and cell membrane were detected using semi-quantitative Western blot.Results1. Lithium-pilocarpine SE model:12 SD rats were induced into SE, one was dead, the overall successful rate was 83.3%.2. The cellular expression levels of GABAA receptor al(1) In hippocampus:the expression levels of GABAA receptor al subunit of SE1 h group and SE2 h group were not significantly changed compared with that of the control group (P＞0.05).(2) In cortex:the expression levels of GABAA receptorα1 subunit of SE1 h group and SE2 h group were not significantly changed, compared with that of the control group (P＞0.05).3. The expression levels of GABAA receptor al in cell membrane(1) In cell membrane of hippocampus:Compared with the control group, the expression levels of GABAA receptorα1 subunit of SE1 h group and SE2 h group were significantly down-regulated (P＜0.01). The decrease of expression levels of GABAA receptor al subunit in SE2 h group was more significantly than that in SE1 h group (P＜0.01);(2) In cell membrane of cortex:Compared with the control group, the expression levels change of GABAA receptorα1 subunit in SE1 h group was not significant (P＞0.05), but that in SE2 h group was significan-tly decreased (P＜0.05).Conclusions 1. The longer SE duration is, the more significant down-regulated of GABAA receptors al expressing occurs in the cell membrane.2. There is no significant influence of SE less than 2 hours on the expression levels of GABAA receptor al subunit in hippocampus and cortex.