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目的和方法 :采用膜片钳技术之膜内面向外记录方法 ,在急性分离大鼠皮层神经元上 ,研究胞内酸碱环境改变对神经元ATP敏感钾通道的影响。结果 :Vp =+6 0mV时 ,pH6 .0组开放概率 2 .2 0 %± 0 .5 7% (n =1 0 )较 pH7.3时的开放概率 8.41 %± 1 .2 0 % (n =1 6 )显著降低 (P <0 .0 1 ) ;pH 8.0组开放概率 1 8.2 9%± 4.0 5 % (n =8)较 pH7.3时明显增加 (P <0 .0 1 )。当浴液由 pH 7.3降为pH 6 .0时 ,有 40 %出现多级通道电流并可逆转。当浴液 pH6 .0及 pH 8.0时 ,ATP抑制通道开放概率的量效曲线 ,与pH 7.3时比较无明显改变 (P >0 .0 5 )。 结论 :脑细胞内氢离子可能参与KATP通道的调节 :胞内酸化环境可进一步激活KATP通道多级电流 ,保护脑缺血缺氧损伤 ;而KATP,通道开放 ,膜超极化到一定程度 ,胞内酸化环境又可抑制通道开放。
PURPOSE AND METHODS: The effects of intracellular pH changes on ATP-sensitive potassium channel in neurons were studied in vitro by patch-clamp technique. Results: At Vp = +60 mV, the open probability of pH6.0 group was 2.0% ± 0.57% (n = 10) and the open probability was 8.41% ± 1.2% (n = 1 6) (P <0.01). The open probability of pH 8.0 group was significantly higher than that of pH 7.3 at 1 8.29% ± 4.0 5% (n = 8) (P <0.01). When the bath was reduced from pH 7.3 to pH 6.0, 40% of the channels appeared multistage and reversible. When the bath pH6.0 and pH 8.0, ATP dose-effect curve of inhibiting the open probability of channel, compared with the pH 7.3 no significant change (P> 0.05). CONCLUSION: Hydrogen ions in brain cells may be involved in the regulation of KATP channel: intracellular acidification can further activate KATP channel multi-level current to protect cerebral ischemia and hypoxia injury; while KATP, channel opening, membrane hyperpolarization to a certain extent, Acidification within the environment can inhibit the open channel.