Ethanol-induced preferences or aversions as a function of age in preweanling rats.

The reinforcing value of a relatively high ethanol dose (3 g/kg) administered intragastrically was investigated in preweanling rats. Ethanol intoxication on Postnatal Days 7-8 increased ethanol intake and enhanced the drug's palatability when tested 3 days later. In contrast, intoxication on Days 10-11 decreased ethanol intake and increased aversive responses to the drug. When reducing the delay between intoxication and test to 24 hr, the taste aversion was enhanced, whereas the preference was unaffected. Results suggest an ontogenetic change in pups' perception of the reinforcing value of ethanol that coincides with the end of a sensitive period for learning preferences in rats younger than 9 days old (T. L. Roth & R. M. Sullivan, 2003; R. M. Sullivan, M. Landers, B. Yeaman, & D. A. Wilson, 2000).