Recent advances in animal models of alcohol craving and relapse

Animal models designed to examine different facets of alcohol-related behaviors have been developed to study genetic and neurobiological factors underlying alcoholism and alcohol abuse. One goal has been to develop valid, congruent, complementary animal models of alcohol craving and relapse, with the ultimate objective of assessing the effectiveness of pharmacological agents with these models. Animal models of alcohol craving include drug-induced responding (drug reinstatement), cue-induced responding, Pavlovian Spontaneous Recovery (PSR), and appetitive/consummatory responding. A primary experimental approach to study alcohol relapse has been through expression of the Alcohol Deprivation Effect (ADE) following a single deprivation or multiple deprivations. To date, five selectively bred lines of rats have been developed to study alcohol-drinking behavior. These are the ALKO/Alcohol (AA), alcohol-preferring (P), high alcohol-drinking (HAD-1 and HAD-2 replicates), and the Sardinian alcohol-preferring (sP) lines of rats. Findings thus far indicate that only the P line of rats meets all the criteria established for a valid animal model of alcoholism, with progress having been made in characterizing the AA, HAD and sP lines of rats. The focus of the current review will be to analyze the various models of alcohol craving, emphasizing the use of the Indiana University selected rat lines (P and HADs). Overall, the findings indicate substantial progress has been made in developing animal models of alcohol abuse, relapse and craving using these selectively bred rat lines, as well as outbred rats.