PROTECTIVE EFFECT OF MORPHINE ON ETHANOL-INDUCED GASTRIC-LESIONS IN RATS - ARE ATP-DEPENDENT POTASSIUM CHANNELS INVOLVED

Morphine has a significant protective effect on ethanol-induced gastric lesions. This effect is antagonized by naloxone, suggesting the involvement of opioid receptors. The ATP-dependent potassium channel blockers glibenclamide and phentolamine have different effects on this action of morphine. While glibenclamide potentiates the gastroprotective effect of morphine, phentolamine antagonizes it. However, both prazosin and yohimbine do not affect the gastroprotective action of morphine, suggesting that the influence of phentolamine is not mediated by alpha-adrenoceptors. As phentolamine also prevented the gastroprotective effect of the ATP-dependent K+ channel opener diazoxide, our results suggest that ATP-dependent K+ channels may be involved in the gastroprotective action of morphine.