Evaluating voluntary abstinence from ethanol self-administration in rats using a concurrent-chains procedure

This pilot study aimed to examine voluntary abstinence from, and relapse of, ethanol seeking following removal of alternative nondrug reinforcement using a concurrent-chains arrangement. Rats first were trained to self-administer ethanol during a baseline condition. Next, they were presented with choices between responding for ethanol and sucrose during the initial link of a concurrent-chains schedule. Following their initial-link choice, they entered a terminal link in which they could respond exclusively for the reinforcer associated with their initial-link choice. To test for relapse, the same concurrent-chains procedure was arranged except that sucrose reinforcement was suspended from the sucrose-correlated terminal link. Overall, four out of the five rats showed a consistent preference for sucrose over ethanol during the voluntary-abstinence phase. When sucrose reinforcement was suspended during the relapse test, ethanol seeking increased for all rats.