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
em En
| LILACS
| ID: lil-197262
Biblioteca responsável:
BR1.1
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.
Texto completo:
1
Índice:
LILACS
Assunto principal:
Potássio
/
Técnicas In Vitro
/
Permeabilidade da Membrana Celular
/
Canais de Cloreto
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Braz. j. med. biol. res
Assunto da revista:
BIOLOGIA
/
MEDICINA
Ano de publicação:
1997
Tipo de documento:
Article