Mechanisms of action of drugs of abuse on the developing fetal brain.

The consequences of public health of the acquisition and use of drugs of abuse have been well demonstrated. Despite intense effort, however, progress has been slow in recent years in ascertaining the specific neurodevelopmental effects of these drugs on the children of drug-abusing mothers. The use of animal models allows the investigator to determine the specific biological contributions of prenatal exposure to drugs of abuse on neurodevelopmental outcome while controlling for covariates that have confounded clinical studies, such as altered nutrition in pregnancy, suboptimal rearing environment of the young, and availability of drug and nondrug stimulation to the offspring. This article selectively reviews the preclinical literature on the gestational effects of drugs of abuse with particular emphasis on cocaine, ethanol, and the opiate narcotics. Mechanisms of drug action on the mature and developing brain are summarized. A model of developmental impact on the brain regions underlying drug-induced reward and reinforcement and its potential postnatal importance is presented.