CONICET | Buscador de Institutos y Recursos Humanos

Prenatal ethanol exposure modifies postnatal affinity to the drug, increasing the probability of ethanol use and abuse. The present study tested developing rats (five-day-old) in a novel operant technique to gain access to ethanol self-administration as a result of prenatal exposure to low ethanol doses during late gestation. On a single occasion during each of gestational days 17?20, pregnant rats were intragastrically administered ethanol (0 or 1 g/kg). On postnatal day 5, pups were tested on a novel operant conditioning procedure in which they learned to touch a sensor to obtain 0.1% saccharin, 3% ethanol or 5% ethanol. Immediately after a 15-min training session, a 6-min extinction session was given in which operant behavior had no consequence. Pups were positioned on a smooth surface and had access to a touch-sensitive sensor. Physical contact with the sensor activated an infusion pump, which served to deliver intraoral solution as reinforcement (Paired group). A Yoked control animal evaluated at the same time received the reinforcer when its corresponding Paired pup touched the sensor. Operant behavior to gain access to 3% ethanol was facilitated by prenatal exposure to ethanol during late gestation. In contrast, operant learning reflecting ethanol reinforcement did not occur in control animals prenatally exposed to only water. Similarly, saccharin reinforcement was not affected by prenatal treatment. These results suggest that in five-day-old rats prenatal exposure to a low ethanol dose facilitates operant learning reinforced by intraoral administration of a low ethanol concentration solution. This emphasizes the importance of intrauterine experiences with ethanol in later susceptibility to drug reinforcement. The present operant conditioning technique represents an alternative tool to assess self-administration and seeking behavior during early stages of development.