Accumulating evidence shows a key function for astrocytic connexin43 (Cx43) signaling in epilepsy. However, the lack of experimental distinction between Cx43 gap junction channels (GJCs) and hemichannels (HCs) has impeded the identification of the exact contribution of either channel configurations to epilepsy. We therefore investigated whether TAT-Gap19, a Cx mimetic peptide that inhibits Cx43 HCs but not the correspond-ing Cx43 GJCs, influences experimentally induced seizures in rodents. Dye uptake experiments in acute hippo-campal slices of mice demonstrated that astroglial Cx43 HCs open in response to the chemoconvulsant pilocar-pine and this was inhibited by TAT-Gap19. In vivo, pilocarpine-induced seizures as well as the accompanying in-crease in D-serine microdialysate levels were suppressed by Cx43 HC inhibition. Moreover, the anticonvulsant action of TAT-Gap19 was reversed by exogenous D-serine administration, suggesting that Cx43 HC inhibition protects against seizures by lowering extracellular D-serine levels. The anticonvulsive properties of Cx43 HC in-hibition were further confirmed in electrical seizure mouse models, i.e. an acute 6 Hertz (Hz) model of refractory seizures and a chronic 6 Hz corneal kindling model. Collectively, these results indicate that Cx43 HCs play a role in seizures and underscore their potential as a novel and druggable target in epilepsy treatment.%越来越多的证据表明,星形胶质细胞连接蛋白43(Cx43)信号在癫痫中发挥至关重要的作用.但是,由于通过实验方法鉴别Cx43间隙连接通道(GJCs)和半通道(HCs)的技术尚不成熟,导致目前尚无法确定哪个通道在癫痫的发生中发挥更重要的作用.因此,本研究观察TAT-Gap19(Cx模拟肽)是否通过抑制Cx43半通道而非Cx43间隙连接通道影响实验诱导的啮齿动物癫痫发作.急性海马切片小鼠染料摄取实验表明,星形胶质Cx43半通道响应化学惊厥毛果芸香碱的作用而开放,并且可被TAT-Gap19抑制.体内实验中,毛果芸香碱诱导的癫痫发作及相伴随的D-丝氨酸微透析液的增长水平被Cx43半通道的抑制所抑制.此外,TAT-Gap19的抗惊厥作用被外源性D-丝氨酸给药逆转,这表明,抑制Cx43半通道可以通过降低细胞外D-丝氨酸水平来防止癫痫发作.抑制Cx43半通道的抗惊厥特性在电癫痫小鼠模型(如急性6 Hz难治性癫痫发作模型和慢性6 Hz角膜点燃模型)中得到了进一步的证实.总而言之,这些结果表明,Cx43半通道在癫痫发作中可以起到一定作用,并且有成为癫痫治疗中新型用药靶点的潜力.
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