J. Tamaoki et al., ROLE OF K-K+ ATPASE ACTIVITY IN AIRWAY RELAXATION INDUCED BY SALBUTAMOL( CHANNEL OPENING AND NA+), Life sciences, 55(11), 1994, pp. 217-223
Citations number
12
Categorie Soggetti
Biology,"Medicine, Research & Experimental","Pharmacology & Pharmacy
To determine the role of K+ channel opening and Na+-K+ ATPase activity
in the beta-adrenoceptor-mediated relaxation of airway smooth muscle,
we studied canine bronchial segments under isometric conditions in vi
tro. Relaxant responses to salbutamol were not altered by glibenclamid
e or apamin but inhibited by charybdotoxin, where significant inhibiti
on was observed only at salbutamol concentrations of less than 10(-6)
M. In contrast, only the relaxations induced by salbutamol at 3 x 10(-
6) M and greater were sensitive to ouabain. Relaxations produced by lo
w and high concentrations of salbutamol were selectively attenuated by
charybdotoxin and ouabain, respectively, in a concentration-dependent
manner. These results suggest that both Ca2+-activated K+ channel and
Na+-K+ ATPase may be operative in the airway relaxation induced by lo
w and high concentrations of the beta-adrenergic agonist, respectively
.