The Role Of Two Pore Potassium Channel TREK-1on Glutamate Metabolism In Ischemia Astrocytes

Objective:1. To study the effects of the expression of two pore potassium channel TREK-1in astrocytes and the uptake function of glutamate when oxygen glucose is deprivated.2. To study the regulation of excitotoxicity when the expression of astrocytes TREK-1channels changed.Methods:1, We took the classical model of cerebral ischemia in vitro (oxygen-glu cose deprivation model (OGD)) and analysed the changes of expression of two pore potassim channels TREK-1in astrocytes and the uptake function of glutamate.2. We used agonist arachidonic acid (AA) of TREK-1and the inhibitors of methionine (M) and carried on the OGD experiment. We took the method of MTT to detect cell survival rates and used the staining method of Hoechst33258to detect the cell mortality. Besides, we taked the method of FITC/Propidium Iodide double staining to detect stellate cell apoptosis rates and used RT-PCR to detect the changs of astrocyte specificity glutamate transporter GLT-1mRNA, NR2B-1mRNA, Mglur-1mRNA, Caspase-3mRNA, Trek-1mRNA and Erk-lmRNA.Results:1. In vitro cerebral ischemia, the expression of TREK-1increased significantly and the uptake function of glutamic acid was more enhanced after OGD4h compared with the normal cultured astrocytes.2. We used agonist arachidonic acid (AA) of TREK-1and the inhibitors of methionine (M) to carry on the OGD experiment. By activating TREK-1channel of AA, it took effects of reducing the toxicity of glutamic acid excitotoxicity and increasing the cell survival rate. That means M taked an effect on the TREK-1channel, leading to a significantly increased content of glutamie acid and enhanced excitability toxicity. This reveals that TREK-1has the effect of reducing the glutamate excitotoxicity.Conclusions:1. The expression of two pore potassium channels TREK-1in astrocytes and the uptake function on glutamate are both enhanced when oxygen glucose is deprivated.2. The excitoxicity of glutamate can be reduced if the two pore potassium channels TREK-1in astrocytes are activated.