Voltage-dependent and Ca2(+)-activated ion channels in human neutrophils.
J Clin Invest
; 85(2): 491-8, 1990 Feb.
Article
em En
| MEDLINE
| ID: mdl-2153708
ABSTRACT
To investigate the regulation of membrane voltage and transmembrane ion fluxes in human neutrophils, we studied plasma membrane currents using the whole-cell patch-clamp method. We observed three distinct ion channel currents (a) a voltage-dependent K+ current, (b) a Ca2(+)-activated K+ current, and (c) a Ca2(+)-activated Cl- current. The voltage-dependent K+ current was found in cells at rest. Its conductive properties suggested an inwardly rectifying channel. The channel was activated at membrane potentials more positive than -60 mV, suggesting that it may determine the resting membrane potential of neutrophils. Activation of neutrophils by the Ca2+ ionophore ionomycin led to an increase in whole-cell K+ and Cl- currents. The Ca2(+)-activated K+ channel differed from the voltage-dependent K+ channel because it was insensitive to voltage, because it rectified outwardly, and because the voltage-sensitive K+ channel was Ca2(+)-independent. The Ca2(+)-activated Cl- channel showed outward rectification and no apparent voltage dependency. The Ca2(+)-activated K+ and Cl- channels may play a role in cell volume homeostasis and/or cellular activation.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Canais de Potássio
/
Cloretos
/
Cálcio
/
Proteínas de Membrana
/
Neutrófilos
Limite:
Humans
Idioma:
En
Revista:
J Clin Invest
Ano de publicação:
1990
Tipo de documento:
Article