The synergism between ethanol and stress is mediated by CRF1 receptors in preweanling rats

ARIAS, C.; SOLARI, A.C.; MOLINA, J.C.; SPEAR, N.E.

Congreso; International Society for Developmental Psychobiology; 2010

Preweanling rats are highly sensitive to the locomotor stimulation induced by relatively high ethanol doses, an effect rarely observed in adult rats. In adult mice ethanol-mediated stimulation is modulated by stress. The goal of the present study was to analyze the role of stress and stress-related hormones in the stimulating effect of ethanol in preweanling rats. In Experiment 1 15-day-old rats were separated from the mother during a period of 4 h in which subjects remained isolated or paired with a littermate. In a third condition pups remained in the home-cage with the dam. This isolation procedure significantly increased corticosterone levels. Inmediately after subjects received ethanol (0 or 2.5 g/kg) and were tested in a novel environment. Experiment 2 evaluated the effect of exogenous administration of corticosterone (0, 3 or 6 mg/kg) along with ethanol, and Experiment 3 tested ethanol-mediated locomotor activation in adrenalectomized preweanling rats. In Experiment 4 isolated pups were treated with CP154,526 (a corticotropic releasing factor 1 abtagonist) before ethanol administration. Results of the present study revealed a strong synergism between stress or corticosterone and ethanol in preweanling rats. The interaction between stress (induced by social isolation) and ethanol cannot be explained by differential ethanol metabolism in stressed pups compared to non-stressed, and this synergism seems to be mediated by CRF1 receptors. This study highlights the importance of considering stress as a possible intervening variable in studies evaluating ethanol effects in developing animals when maternal separation is used in the experimental procedure.