Fast and slow voltage modulation of apical Cl- permeability in toad skin at high [K+]
Braz. j. med. biol. res
;
30(8): 1033-44, Aug. 1997. ilus
Article
in English
| LILACS
| ID: lil-197262
ABSTRACT
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.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Potassium
/
In Vitro Techniques
/
Cell Membrane Permeability
/
Chloride Channels
Type of study:
Prognostic study
Limits:
Animals
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
1997
Type:
Article
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