Apical membrane properties and amiloride binding kinetics of the human descending colon.
Apical membrane properties and amiloride binding kinetics of the human descending colon.
复制标题
人降结肠的顶膜特性和阿米洛利结合动力学。
DOI：
10.1152/ajpgi.1984.247.6.g749
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Binder,HJ
中科院分区：
文献类型：
--
作者：
Wills,NK;Alles,WP;Sandle,GI;Binder,HJ
应用电流波动分析法和微电极技术对人离体降结肠顶端膜的特性进行了研究。Na+通道阻滞剂阿米洛利用于评估顶端膜电导和跨上皮短路电流（Isc）。阿米洛利显著降低Isc，增加膜阻力比。在次最大剂量的阿米洛利在粘膜浴溶液中，波动分析的Isc揭示了洛伦兹分量的功率密度谱。阿米洛利和电流噪声参数之间的剂量-反应关系与阻断剂与通道相互作用的双态机制一致。对阻断剂-受体反应的开和关速率常数、单通道电流和Na+通道密度进行了估计，与其他所谓的紧密上皮细胞的Na+通道的开和关速率常数相似。此外，这些研究揭示了阿米洛利不敏感的电导在顶膜平行的阿米洛利阻断的Na+通道。这种电导可能是由于钾离子。如果是这样的话，人类降结肠的顶膜特性可能与兔降结肠和大鼠远端结肠的顶膜特性非常相似。
The apical membrane properties of the isolated human descending colon were characterized by use of current fluctuation analysis methods and microelectrode techniques. The Na+ channel blocker amiloride was used to evaluate apical membrane conductance and the transepithelial short-circuit current (Isc). Amiloride significantly reduced Isc and increased the membrane resistance ratio. At submaximal doses of amiloride in the mucosal bathing solution, fluctuation analysis of the Isc revealed a Lorentzian component in the power-density spectra. The dose-response relationship between amiloride and current noise parameters was consistent with a two-state mechanism of blocker interaction with the channel. The on and off rate constants for the blocker-receptor reactions, the single-channel currents, and the Na+ channel densitywere estimated and were similar to those from Na+ channels from other so-called tight epithelia. In addition, these studies revealed an amiloride-insensitive conductance in the apical membrane in parallel to the amiloride-blockable Na+ channels. This conductance may be due to potassium ions. If so, the apical membrane properties of the human descending colon may closely resemble those of the rabbit descending colon and rat distal colon.