Prenatal ethanol alters the postnatal expression of ethanol-induced Appetitive and aversive reinforcement

PAUTASSI RM; NIZHNIKOV ME; SPEAR NE

San Francisco

Congreso; 35th Annual Scientific Meeting of the Research Society on Alcoholism; 2012

Research Society on Alcoholism

Prenatal ethanol has a permissive effect on later alcohol consumption, yet the mechanisms underlying this phenomenon are poorly understood. Little is known about the impact of prenatal ethanol on the sensitivity to ethanol’s reinforcing effects. One possibility is that prenatal ethanol exposure makes subjects more sensitive to the appetitive effects of ethanol or less sensitive to ethanol’s aversive consequences. The present study assessed ethanol-induced second-order conditioned place preference and aversion and ethanol-induced conditioned taste aversion (CTA), with varied ethanol doses, in infant rats derived from pregnant rats administered vehicle or 2 g/kg ethanol during gestational days 17–20. The involvement of the kappa opioid receptor system in the aversive effects of ethanol was also explored. When place conditioning occurred during the rising limb of the blood-ethanol curve (Experiment 1) pups exposed to ethanol in-utero, but not controls, exhibited conditioned place preference. Conditioning during a later phase of the intoxication (30–45 min post-administration, Experiment 2) resulted in place aversion in control pups but not in those that had been exposed to ethanol in-utero. Ethanol readily induced conditioned taste aversion (Experiment 3), which was fairly similar across pups treated with vehicle or ethanol during gestation. The administration of a kappa antagonist (norbinaltorphimine) 24 hrs before conditioning did not alter ethanol-induced CTA. These results suggest that a relatively brief exposure to a moderate ethanol dose during late gestation tilts the balance between ethanol’s appetitive and aversive effects, promoting the expression of ethanol-mediated conditioned reinforcement and blocking the acquisition of conditioned aversion by ethanol. This altered pattern of motivational reactivity to ethanol could be one of the mechanisms underlying the permissive effect that prenatal ethanol exerts in later ethanol aceptance