Assessment of reinforcing effects of etanol in 15-day old rats through a self-administration paradigm

MACARENA FERNÁNDEZ; NICOLAS SANCHEZ; PAULA ABATE; PAUTASSI RM

Valparaiso

Workshop; II International Workshop: Motivated behaviors, stress and addiction: from molecules to behavior?; 2012

Latin America Research Network in Drug Abuse

It is important to analyze the effects of ethanol during early development. Early alcohol exposure is an important determinant of later alcohol intake. Previous studies suggest that infant rats (Ponce et al., 2008; Miranda-Morales et al., 2012) can learn to self-administer ethanol without the need of extensive training procedures. In the present study we aimed at replicating these results as well to analyze the best parameters (in terms of ethanol concentration and volume of reinforcement) to induce ethanol reinforcement. Two-week old rats were placed in plexiglass chambers equipped with a small hole in a corner. Each poke in the hole activated an infusion pump that delivered ethanol or sucrose into the oral cavity. In controls animals the emission of nose pokes and access to the reinforcer were explicitly unpaired. Daily training sessions (duration: 15 min) were conducted on postnatal days 15 to 18. Experiment 1 indicated that this procedure reliable induced substantial sucrose self- administration. In Experiment 2 each nose poke was reinforced with 2 or 10 ul of either 2% or 5% ethanol (vehicle: distilled water). ANOVAs indicated significant responding for ethanol, when compared with control subjects. Responding was slightly higher in animals given 10 ul of 5% after each. Gas chromatography analyses indicated measurable blood ethanol levels in some, yet not all, of these animals. Overall, these results indicate that this technique may be useful to analyze determinants of ethanol self-administration during development.