Resumption of morphine self-administration by ex-addict rats: An attempt to modify tendencies to relapse.

Abstract

Studied relapse tendencies in 69 morphine-dependent male hooded rats which had learned to drink bitter solutions of the drug in preference to water. Prolonged enforced abstinence (110 days) did not prevent Ss from resuming self-administration of morphine. Since the bitter taste of morphine may have become a secondary reinforcer, an attempt was made to extinguish responding for this source of reward. Abstinence was shortened to 12 days, during which Ss were given solutions of quinine to drink. On subsequent relapse tests these Ss consistently took less morphine than controls. Ss injected with methadone during the 1st 8 days of abstinence initially consumed slightly more morphine on relapse tests than did controls, but this difference was not maintained. (22 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)