Effects of alpha-methyl-p-tyrosine on morphine depnendence.

Abstract

The effects of alpha-methyl-p-tyrosine (aMpT) on the initial liability to consume oral morphine solution and on withdrawal following cessation of passive morphine administration were assessed. aMpT depressed consumption of oral morphine solution if aMpT was administered throughout a nine day period of morphine intake; when aMpT administration was stopped a day prior to presentation of morphine solution, subsequent intakte of morphine was enhanced. Following cessation of passive morphine administration, aMpT was found to ameliorate withdrawal-induced weight loss; this effect occurred to a similar extent regardless of whether aMpT was administered only during the first withdrawal day, only on days of morphine administration or during both periods of morphine administration and withdrawal. These results implicate an important role of catecholamines in addiction and dependence to morphine.