Glibenclamide antagonizes the inhibitory effect of morphine on gall bladder emptying

Egg yolk-induced gall-bladder emptying in mice was used to investigate the effect of glibenclamide and minoxidil (ATP-dependent K(+)-channel modulators) on biliary tract effects of morphine. The inhibitory effect of morphine (1-4 mg kg-1, i.p.) on egg yolk-induced gall-bladder emptying was completely blocked by pretreatment with naloxone (2 mg kg-1, i.p.) or glibenclamide (0.65 mg kg-1, i.p.) whereas, pretreatment with minoxidil (0.65 mg kg-1, i.p.) did not modify the inhibitory effect of morphine on gall-bladder emptying. Our results suggest that biliary-tract actions of morphine are mediated through glibenclamide-sensitive K+ channels similar to those involved in the analgesic action of morphine.