Reconstitution of a KATP channel from basolateral membranes of Necturus enterocytes.
Reconstitution of a KATP channel from basolateral membranes of Necturus enterocytes.
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从 Necturus 肠细胞基底外侧膜重建 KATP 通道。
DOI：
10.1152/ajpcell.1995.269.2.c464
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Schultz,SG
中科院分区：
文献类型：
--
作者：
Mayorga-Wark,O;Dubinsky,WP;Schultz,SG
我们以前曾报道过，基底外侧膜囊泡分离出的Necturus maculosa小肠上皮细胞，并纳入平面磷脂双层显示一个高度选择性的“最大”电导K+通道，其开放时间的概率受电压的影响。我们现在报告说，该通道被MgATP抑制的解决方案洗澡的细胞内面对的通道，但不是由Mg 2+或Na+或K+盐的ATP; MgATP的效果可以防止或逆转的MgADP。该通道也被不可水解的ATP类似物腺苷5 '-O-（3-硫代三磷酸）镁和磺酰脲衍生物甲苯磺丁脲和格列本脲抑制;所有这些药物在细胞内室中有效，但单独加入细胞外室时无效。“K+通道开放剂”二氮嗪可刺激通道活性，也可逆转格列本脲的作用，但不逆转MgATP的作用。这个通道可能的作用，作为一个调解人之间的平行基底外侧膜Na（+）-K+泵活性和宏观K+电导的障碍进行了讨论。
We have previously reported that basolateral membrane vesicles isolated from Necturus maculosa small intestinal epithelial cells and incorporated into planar phospholipid bilayers display a highly selective "maxi"-conductance K+ channel whose open-time probability is affected by voltage. We now report that this channel is inhibited by MgATP in the solution bathing the intracellular face of the channel but not by Mg2+ or the Na+ or K+ salts of ATP; the effects of MgATP can be prevented or reversed by MgADP. The channel is also inhibited by the nonhydrolyzable ATP analogue magnesium adenosine 5'-O-(3-thiotriphosphate) and the sulfonylurea derivatives tolbutamide and glibenclamide; all of these agents are effective in the intracellular compartment but not when added to the extracellular compartment alone. Channel activity is stimulated by the "K+ channel opener," diazoxide, which also reverses the effect of glibenclamide but not of MgATP. The possible role of this channel as a mediator of the parallelism between basolateral membrane Na(+)-K+ pump activity and the macroscopic K+ conductance of that barrier is discussed.