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
Article
in English
| 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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Index:
LILACS (Americas)
Main subject:
Sodium
/
Cell Membrane Permeability
/
Calcium
/
Amiloride
Type of study:
Diagnostic study
/
Prognostic study
Limits:
Animals
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
1991
Type:
Article
/
Congress and conference
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