Ca2+ induced down-regulation of epithelial amiloride-sensitive channels reconstituted into planar lipid bilayers
Braz. j. med. biol. res
;
24(1): 123-6, jan.-mar. 1991. ilus
Artigo
em Inglês
| LILACS
| ID: lil-99591
ABSTRACT
Multichannel experiments were carried out to investigate the Ca2+ - induced down-regulation of epithelial Na+ channels reconstituted into planar lipid bilayer membranes. Reconstitution was achueved by fusion of vesiculated apical membrane fragments to solvent-free planar lipid bilayers. We found that the presence of micromolar concentrations of Ca2+ on the side to which the vesicles were added substantially lowered the channel-mediated current. The inhibition was strongly influenced by pH. At pH 8.0 all the current was blocked by 1 mM calcium, whereas at pH 7.1 the inhibition was about 80%. The blocking kinetics was clearly voltage-dependent. The mechanism of blocking cannot be explained either in terms of interations with a single site, or by a model in which two blocking sites are assumed.
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Índice:
LILACS (Américas)
Assunto principal:
Sódio
/
Permeabilidade da Membrana Celular
/
Cálcio
/
Amilorida
Tipo de estudo:
Estudo diagnóstico
/
Estudo prognóstico
Limite:
Animais
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
1991
Tipo de documento:
Artigo
/
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