Involvement of K(+) channel in procainamide-induced relaxation of bovine tracheal smooth muscle.
Eur J Pharmacol
; 402(1-2): 143-9, 2000 Aug 18.
Article
em En
| MEDLINE
| ID: mdl-10940368
ABSTRACT
The relaxant effect of procainamide, a class Ia antiarrhythmic agent, was examined in bovine tracheal smooth muscle. Procainamide produced concentration-dependent decreases in tension and full relaxation in the preparations contracted with methacholine (0.3 microM). By comparison, in preparations contracted with 40 mM K(+), procainamide had only slight relaxant effects. The relaxant effects of cromakalim and salbutamol on 40 mM K(+)-contracted preparations were significantly (P<0.01) smaller than those on 0.3 microM methacholine-contracted ones. On the other hand, the concentration-response relationships for quinidine, lidocaine, mexiletine and propafenone were not so dramatically different between 0.3 microM methacholine- and 40 mM K(+)-contracted preparations. Tetraethylammonium (300 microM), iberiotoxin (30 nM) and Ba(2+) (1 mM) significantly (P<0.05) attenuated the relaxant effects of procainamide on methacholine-induced contractions, whereas apamin (100 nM), 4-aminopyridine (300 microM), and glibenclamide (10 microM) did not affect them. The inhibitory effect of a combination of iberiotoxin and Ba(2+) was greater than that of iberiotoxin or Ba(2+) alone (P<0.01). These results suggest that the activation of at least two types of K(+) (maxi-K(+) and inward rectifier K(+)) channels contributes to the procainamide-induced relaxation of bovine tracheal smooth muscle.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Procainamida
/
Traqueia
/
Canais de Potássio
/
Antiarrítmicos
/
Músculo Liso
Limite:
Animals
Idioma:
En
Ano de publicação:
2000
Tipo de documento:
Article