The effect of carbon monoxide on contraction, cytosolic Ca2+ level and ionic currents in guinea pig ileal smooth muscle
The Korean Journal of Physiology and Pharmacology
; : 479-486, 2000.
Article
em En
| WPRIM
| ID: wpr-728127
Biblioteca responsável:
WPRO
ABSTRACT
The aim of this study was to clarify the mechanism of the inhibitory action of carbon monoxide (CO) on contraction, by measuring cytosolic Ca2+ level ((Ca2+)i) and ionic currents in guinea-pig ileum. CO (10%) inhibited 40 mM KCl-induced contraction and this effect was blocked by ODQ (1 micrometer), a soluble guanylyl cyclase (sGC) inhibitor. CO inhibited the 40 mM KCl-induced contraction without changing (Ca2+)i. Cumulative addition of KCl induced a graded increase in (Ca2+)i and muscle tension. In the presence of CO, cumulative addition of KCl induced smaller contraction than in the absence of CO. On the other hand, the increase in (Ca2+)i induced by cumulative addition of KCl was only slightly decreased in the presence of CO, and the (Ca2+)i-tension relationship shifted downwards. Using the patch clamp technique with a holding potential of -60 mV, we found that CO had little effect on the peak Ba currents (IBa) when voltage was stepped from -60 mV to 0 mV. In addition, CO showed no effect on the depolarization-activated outward K+ currents in the all potential ranges. We conclude that CO inhibits smooth muscle contraction mainly by decreasing the Ca2+ sensitivity of contractile elements via a cGMP-dependent pathway, not by involving L-type Ca2+ and outward-potassium currents in guinea-pig ileum.
Palavras-chave
Texto completo:
1
Base de dados:
WPRIM
Assunto principal:
Carbono
/
Monóxido de Carbono
/
Guiné
/
Citosol
/
Guanilato Ciclase
/
Cobaias
/
Mãos
/
Íleo
/
Músculo Liso
/
Tono Muscular
Limite:
Animals
País/Região como assunto:
Africa
Idioma:
En
Revista:
The Korean Journal of Physiology and Pharmacology
Ano de publicação:
2000
Tipo de documento:
Article