Ethanol-mediated operant learning in the infant rat leads to increased ethanol intake during adolescence.

Recent studies indicate that the infant rat has high affinity for ethanol ingestion and marked sensitivity to the drug's reinforcing effects [Spear, N.E., Molina, J.

Infantile sensitivity to ethanol's motivational effects: Ethanol reinforcement during the third postnatal week.

Background: Although tests specific to newborn rats have frequently verified their susceptibility to the reinforcing properties of ethanol, demonstration of comparable reinforcing effects in older infants has been elusive. Using a second-order conditioning procedure, the present study assessed in preweanling rats whether pairing with early postabsorptive effects of ethanol would render intraorally delivered gustatory stimuli capable of positive reinforcement for association with a salient texture. Direct reinforcing effects of ethanol were also evaluated through intake tests of gustatory stimuli previously paired with the drug.

Acute ethanol counteracts the acquisition of aversive olfactory learning in infant rats.

Rodents are particularly prone to acquire associative memories during early stages of life. Yet, very little is known about how ethanol interacts with simultaneous associative learning acquired during postabsorptive periods. We have recently observed that preweanling rats avoid lemon odor previously paired with the intraoral infusion of a sapid sweet solution, a result likely to be caused by aversive consequences inherent to this procedure.