Inhibitory mechanism of monensin on high K+-induced contraction in guniea-pig urinary bladder.
J Pharmacol Sci
; 100(2): 133-41, 2006 Feb.
Article
en En
| MEDLINE
| ID: mdl-16474206
ABSTRACT
In this study, we examined the inhibitory mechanism of monensin on high K+-induced contraction in guinea-pig urinary bladder. The relaxant effect of monensin (0.001 - 10 microM) was more potent than those of NaCN (100 microM - 1 mM) and forskolin (3 - 10 microM). Monensin (0.1 microM), NaCN (300 microM), or forskolin (10 microM) inhibited high K+-induced contraction without decreasing [Ca2+]i level. Monensin and NaCN remarkably decreased creatine phosphate and ATP contents. Monensin and NaCN inhibited high K+-induced increases in flavoprotein fluorescence, which is involved in mitochondrial respiration. Forskolin increased cAMP content but monensin did not. Monensin increased Na+ content at 10 microM but not at 0.1 microM that induced maximum relaxation. In the alpha-toxin-permeabilized muscle, forskolin significantly inhibited the Ca2+-induced contraction, but monensin did not affect it. These results suggest that the relaxation mechanism of monensin in smooth muscle of urinary bladder may be an inhibition of oxidative metabolism.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Potasio
/
Vejiga Urinaria
/
Monensina
/
Contracción Isométrica
/
Músculo Liso
Límite:
Animals
Idioma:
En
Revista:
J Pharmacol Sci
Asunto de la revista:
FARMACOLOGIA
Año:
2006
Tipo del documento:
Article
País de afiliación:
Japón