A variety of animal models are available to study the cardinal features of drug dependence (23, 33–45). The effects of PPAR agonists have been evaluated using animals models for the subjective effects of drugs (drug discrimination), their rewarding/reinforcing effects (intravenous drug self-administration), the influence of environmental factors on drug-seeking behavior (reinstatement of extinguished drug-seeking behavior and other relapse models, sensitization) and the withdrawal states associated with abrupt termination of drug action. We will review the results obtained so far with these various procedures, focusing on operant drug self-administration models, the preeminent animal model of drug abuse.
