Ethanol exposure during late gestation: Long-term sensitization to hedonic properties of a natural reinforcer

CULLERÉ, ME; SPEAR, N.E.; MOLINA, J.C.

Atlanta

Congreso; 34th Annual Scientific Meeting of the Research Society on Alcoholism; 2011

Rsearch Society on Alcoholism

Reinforcing properties of ethanol are perceived early in life. Ingfant rats express appetitive and aversive ethanol-mediated learning as a function of drug dose and post-administration time (Molina et al., 2007). We have previously reported that ethanol´s unconditioned properties interact with hedonic properties of natural reinforcers leading to inflation or deflation of an original memory, depending mainly on the ethanol dose administered. This study aims at assessing if prenatal ethanol experience shifts the mentioned revaluation capacity of ethanol. Pregnant rats received 0 or 2 g/kg ethanol during late gestation. Between postnatal days 14-16 infant rats derived from these gestational treatments were trained in an operant task where nose-poke behavior was reinforce with an intraoral infusion of sucrose (10% v/V). On PD 17 animals were re-exposed to sucrose while experiencing ethanol (0, 0.5 or 2.5 g/kg). Operant responding for sucrose was latter assessed. Pups from ethanol-treated dams exhibited significantly more nose pokes than controls during training. After revaluation a deflation effect was observed in pups given 2.5 g/kg ethanol, whereas the lowest dose induced an inflation effect in animals corresponding to vehicle-treated dams. Pups from ethanol treated dams exhibited higher responding during extinction. These results confirm previous studies indicating that ethanol´s postabsorptive effects can inflate or deflate the reinforcing value of sucrose. It was also observed that fetal ethanol exposure shifted basal thresholds related with hedonic properties of sucrose. It is possible that gestational ethanol experience sensitizes neural substracts involved in natural and pharmacological reinforcement.