CLONIDINE ATTENUATES CONDITIONED AVERSION PRODUCED BY NALOXONE-PRECIPITATED OPIATE WITHDRAWAL

Clonidine, an alpha(2)-adrenoreceptor agonist, is used to alleviate wi thdrawal severity during detoxification from chronic opiate use. The e ffectiveness of clonidine has been challenged because it attenuates so me, but not all, withdrawal signs in humans and animals. Because somat ic assessments may not reflect opiate withdrawal aversion, this study used a one-trial place conditioning procedure. Naloxone was paired wit h the most preferred side and the amount of time spent on this side an d on the vehicle-paired side was measured after training. This procedu re led to a dose-related decrease in the time spent on the naloxone-pa ired side in morphine-exposed rats, but not in non-morphine-exposed ra ts. This conditioned place aversion shown by morphine-exposed rats was significantly attenuated by clonidine. These results suggest that in addition to clonidine's ability to lessen some somatic signs of opiate withdrawal, it also attenuates the aversive aspects of this state.