Bretylium causes a K(+)-Na+ pump activation that is independent of Na+/H+ exchange in depolarized rat, mouse and human lymphocytes.
Mol Immunol
; 27(12): 1307-11, 1990 Dec.
Article
en En
| MEDLINE
| ID: mdl-2177149
ABSTRACT
We have studied a bretylium tosylate induced increase of the membrane potentials of partially depolarized rat, mouse and human lymphocytes, using the potential sensitive dye, bis [1,3, dibutylbarbituric acid-(5) trimethine oxonol]. The extent of this repolarization is dose-dependent and decreased in magnitude as the temp was reduced from 37 degrees C to room temp. The repolarizing effect is inhibited by K(+)-Na(+)-pump blockers or lack of extracellular Na+. Sodium ion channel blockers are effective in abolishing repolarization only if applied prior to, or simultaneously with, bretylium. Activation of Na+/H+ exchange is not involved in the mechanism of the phenomenon as the latter is completely eliminated in the presence of 10 microM amiloride (concn of the diuretics having no measurable inhibition on the action of the exchanger). These data suggest that bretylium opens ligand- and voltage-gated Na+ channels, and repolarization occurs due to higher activity of the K(+)-Na(+)-pump stimulated by the enhanced intracellular Na+ accumulation.
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Banco de datos:
MEDLINE
Asunto principal:
Compuestos de Bretilio
/
Linfocitos
/
ATPasa Intercambiadora de Sodio-Potasio
Tipo de estudio:
Etiology_studies
Límite:
Animals
/
Humans
Idioma:
En
Año:
1990
Tipo del documento:
Article