Involvement of central K ATP channels in the gastric antisecretory action of α 2-adrenoceptor agonists and β-endorphin in rats

Abstract

The intracerebroventricularly (i.c.v.) injected presynaptic α 2-adrenoceptor agonists, clonidine and oxymetazoline, exerted a dose-dependent inhibition on the gastric acid secretion in pylorus-ligated rats; the ED 50 values were 20 and 7.5 nmol/rat, respectively. Moreover, β-endorphin, given i.c.v., also decreased acid secretion (ED 50=0.25 nmol/rat i.c.v.). The antisecretory effect of these compounds was highly reduced by glibenclamide (10 nmol/rat i.c.v.), a selective blocker of K ATP channels. These results suggest that K ATP channels in the central nervous system are likely to be involved in the centrally initiated antisecretory action of both α 2-adrenoceptor agonists and β-endorphin.