哇巴因和零[K⁺]ₒ处理后青蛙缝匠肌纤维的跨膜K⁺、Na⁺和Cl⁻通透性及电导变化

Transmembrane K+, Na+, and Cl- permeability and conductance changes in the frog sartorius fibres following ouabain and zero [K+]o treatment.

作者信息

Hinke J A

出版信息

Can J Physiol Pharmacol. 1987 May;65(5):949-53. doi: 10.1139/y87-151.

Abstract

Changes in the K+, Na+, and Cl- permeabilities (P) and conductances (g) of the intact frog sartorius fibre membrane following ouabain or zero [K+]o treatment were calculated from intrafibre activity and whole muscle electrolyte changes. Conventional equations relating ionic fluxes to resting potential (E), ionic gradient potential, and internal and external ionic activities were used. Both treatments produced a three- to five-fold increase in PNa and gNa. In addition, ouabain produced a fivefold increase in PK (and gK) and a small decrease in PCl (and gCl), whereas zero [K+]o produced a 60% reduction in PK, a 90% reduction in gK, and a threefold increase in PCl (and gCl). When the two treatments were combined, the P and g changes were paradoxical, suggesting that the ouabain-induced increase in gK and the zero [K+]o-induced decrease in gK were occurring but in different channels (or carriers). During ouabain treatment, E reflects mainly the transmembrane K+ gradient potential; during zero [K+]o treatment, E reflects mainly the Cl- gradient potential. Despite channel (or carrier) specificity, it appears that all three ionic permeabilities are altered during the perturbations.

摘要

根据纤维内活性和全肌电解质变化，计算了哇巴因或零[K⁺]ₒ处理后完整青蛙缝匠肌纤维膜的K⁺、Na⁺和Cl⁻通透性（P）及电导（g）的变化。使用了将离子通量与静息电位（E）、离子梯度电位以及细胞内和细胞外离子活性相关联的传统方程。两种处理均使PNa和gNa增加了三到五倍。此外，哇巴因使PK（和gK）增加了五倍，PCl（和gCl）略有下降，而零[K⁺]ₒ使PK降低了60%，gK降低了90%，PCl（和gCl）增加了三倍。当两种处理联合使用时，P和g的变化是矛盾的，这表明哇巴因诱导的gK增加和零[K⁺]ₒ诱导的gK降低同时发生，但发生在不同的通道（或载体）中。在哇巴因处理期间，E主要反映跨膜K⁺梯度电位；在零[K⁺]ₒ处理期间，E主要反映Cl⁻梯度电位。尽管通道（或载体）具有特异性，但在这些扰动过程中，似乎所有三种离子通透性都发生了改变。