Ruthenium red inhibits selectively chromaffin cell calcium channels.
Biochem Pharmacol
; 47(2): 225-31, 1994 Jan 20.
Article
em En
| MEDLINE
| ID: mdl-7508229
ABSTRACT
The effect of Ruthenium red (RR) on ionic currents and catecholamine secretion was studied in chromaffin cells. This polycation inhibited 59 mM potassium-stimulated 45Ca2+ uptake in a concentration-dependent manner (IC50 = 5 +/- 0.2 microM). This effect was more evident at extracellular calcium concentrations over 1 mM and was not abolished by neuraminidase pretreatment. RR also inhibited potassium-stimulated catecholamine secretion (IC50 = 6 +/- 0.9 microM). These results were corroborated by patch-clamp in whole-cell recordings. RR inhibited chromaffin cell calcium currents (IC50 = 7 microM) without affecting significantly either sodium or potassium currents. Radioligand binding studies in adrenomedullary plasma membranes showed that RR inhibited [125I]omega-conotoxin GVIA binding but it had no effect on specific binding of [3H]nitrendipine. The effect of the RR on calcium currents was additive with the inhibitory effect observed with 10 microM nitrendipine. The residual dihydropyridine-resistant calcium current was inhibited with a potency similar to that determined under control conditions in the absence of nitrendipine. These results demonstrate that RR selectively inhibits calcium channels; however, this polycation was not selective for a particular calcium channel subtype.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Rutênio Vermelho
/
Bloqueadores dos Canais de Cálcio
/
Células Enterocromafins
Limite:
Animals
Idioma:
En
Revista:
Biochem Pharmacol
Ano de publicação:
1994
Tipo de documento:
Article
País de afiliação:
Espanha