Tolerance and sensitization induced by ethanol in preweanling rats: posterior effects upon ethanol consumption and taste aversion learning

CASTELLÓ, STEFANÍA.; MOLINA, J.C.; ARIAS, C.

Puerto Varas

Congreso; VIII LASBRA International Meeting: Neurobiological basis of alcoholism: from molecules to behavior; 2017

LASBRA

Chronicethanol exposure can induce two opposite effects upon locomotion inpreweanling rats: tolerance or sensitization. These effects depend onseveral factors,such as context pre-exposure. Prior experience in a salient contextgenerates tolerance. On the contrary, sensitization develops as afunction of the novelty of the testing context. The present studyanalyzed whether chronic ethanol exposure under conditions thatpromote tolerance or sensitization, affects ethanol consumption andethanol-mediated taste aversion learning in preweanlings. Pups wereadministered with water or 2.5 g/kg ethanol (postnatal days, PDs,8-12) and placed in a salient novel context or a context similar tothe maternal cage. During PDs 15-19 pups were tested in terms ofethanol or saccharin consumption. All tests were conducted in thementioned salient context. Saccharin intake was followed by an i.g.administration of ethanol (1.5 or 2.5 g/kg) on PDs 15-17. On PDs18-19, two extinction sessions took place. Pups trained with ethanolunder conditions that favour tolerance development, exhibitedheightened ethanol consumption. Ethanol-treated animals underconditions that favour sensitization showed lower ethanol intakepatterns. Ethanol pre-exposure, independently from conditions thatfavour tolerance or sensitization, was a significant factor leadingto the inhibition of conditioned taste aversions. These resultssuggest that ethanol pre-exposure influences ethanol intake in acontext-dependent manner and that ethanol-mediated taste aversionsare reduced as a function of drug pre-exposure. The results suggestthat ethanol-related early experiences sensitizes the organism to thedrug`s positive reinforcing effects and generates tolerance to itsaversive unconditioned properties.p { margin-bottom: 0.25cm; direction: ltr; line-height: 120%; text-align: left; }a:link { }