新生大鼠纹状体神经元ATP敏感钾通道的特性

Properties of ATP-sensitive K￣+ channels in neonatal rat cultured striatal neurons

为确定纹状体神经细胞膜上存在ＡＴＰ敏感钾通道，用膜片钳技术在培养新生的大鼠纹状体神经元上记录了单通道电流。在细胞贴附式时，胞外给予ＮａＣＮ可诱发一种电导为６０ｐＳ的钾离子单通道，其激活不依赖于膜电位。去极化使通道平均开放时间和开放概率增大。在内面向外式时，ＡＴＰ或优降糖（ｇｌｉｂｅｎｃｌａｍｉｄｅ）均可抑制通道活动，通道激活不依赖于胞内Ｃａ￣（２＋）。结果表明，大鼠纹状体神经细胞膜上存在一种６０ｐＳ的ＡＴＰ敏感钾通道。

n order to determine whether membranes of striatal neurons contain an ATP-sensitive K￣+ Channel,the patch clamp technique was applied to cultured neurons of rat striatum. In cell-attached experiments,ex-tracellular application of NaCN elicited a single K￣+ channel current with a conductance of 60 pS and its ac-tivation was independent on membrane potential. Depolarization increased the mean open time and openprobabilty of these channels. In inside-out patch experiments ,this channel activity was inhibited by an ap-plication of ATP or glibenclamide to the cytoplasmic surface of the patch membrane and the channel activa-tion was independent on intracellular Ca￣(2+)。These results indicate that the neuronal membranes of rat stria-tum contain ATP-sensitive K￣+ channels with a conductance of 60 pS.