Pump-leak parallelism in sodium-absorbing epithelia: the role of ATP-regulated potassium channels.
J Exp Zool
; 279(5): 476-83, 1997 Dec 01.
Article
em En
| MEDLINE
| ID: mdl-9392869
ABSTRACT
In all Na(+)-absorbing and Cl(-)-secreting epithelia, an increase in the activity of the Na+,K(+)-pump at the basolateral membrane is accompanied by an increase in the K+ conductance of that barrier and vice versa. We have recently identified an ATP-regulated K+ channel, K(ATP), in basolateral membrane vesicles isolated from Necturus maculosa small intestinal epithelial cells that could be responsible for this parallelism between pump activity and leak. Thus, an increase in pump activity would result in a decrease in local ATP activity and an increase in local ADP activity and, in turn, an increase in the open-probability of the channel whereas a decrease in in pump activity would have the opposite effect. Further, the likelihood that the number of pumps far exceeds the number of leaks per unit area of membrane suggests that the ATP and ADP activities that influence K(ATP) channel activity may differ markedly from the "bulk" cytoplasmic values.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Canais de Potássio
/
Trifosfato de Adenosina
/
ATPase Trocadora de Sódio-Potássio
Limite:
Animals
Idioma:
En
Revista:
J Exp Zool
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Estados Unidos
País de publicação:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
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US
/
USA