Fast and slow voltage modulation of apical Cl- permeability in toad skin at high [K+]

Brazilian Journal of Medical and Biological Research

J. Procopio¹ 

[1] ,Universidade de São Paulo

关键词: Cl- channel;    toad skin;    voltage modulation;    epithelia;   

DOI  :  10.1590/S0100-879X1997000800018

来源: SciELO

【 摘 要 】

The influence of voltage on the conductance of toad skin was studied to identify the time course of the activation/deactivation dynamics of voltage-dependent Cl- channels located in the apical membrane of mitochondrion-rich cells in this tissue. Positive apical voltage induced an important conductance inhibition which took a few seconds to fully develop and was instantaneously released by pulse inversion to negative voltage, indicating a short-duration memory of the inhibiting factors. Sinusoidal stimulation at 23.4 mM [Cl-] showed hysteresis in the current versus voltage curves, even at very low frequency, suggesting that the rate of voltage application was also relevant for the inhibition/releasing effect to develop. We conclude that the voltage modulation of apical Cl- permeability is essentially a fast process and the apparent slow components of activation/deactivation obtained in the whole skin are a consequence of a gradual voltage build-up across the apical membrane due to voltage sharing between apical and basolateral membranes

【 授权许可】

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