Conditioned preferences in the rat with an unnatural need state: Morphine withdrawal.

Abstract

Placed 30 morphine addicted and 15 nonaddicted female albino rats on a 21-day conditioning regimen which involved the daily alternation of access to either water, sucrose-octa-acetate (SOA), or no liquid for 1 hr. The addicted Ss received injections of morphine after either the SOA sessions or the no-liquid sessions. Nonaddicted Ss were injected with morphine after the SOA sessions. Following the last injection, Ss were given a 2-bottle preference test between SOA and water. Results show that the addicted Ss that received morphine-SOA pairings had an increased preference for SOA, whereas the nonaddicted Ss showed a decrease in SOA preference after the same conditioning treatments. Addicted Ss that received the morphine injections on the no-liquid days showed no change in SOA preference. (21 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)