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

CASTELLO, S.; ARIAS, C.; MOLINA, J.C.

Puerto Varas

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

LASBRA

Chronic ethanol exposure can induce two opposite effects upon locomotion inpreweanling rats: tolerance or sensitization. These effects depend on several factors, such as context pre-exposure. Prior experience in a salient context generates tolerance. On the contrary, sensitization develops as a functionof the novelty of the testing context. The present study analyzed whether chronicethanol exposure under conditions that promote tolerance or sensitization, affects ethanol consumption and ethanol-mediated taste aversion learning in preweanlings. Pups were administered with water or 2.5 g/kg ethanol (postnatal days, PDs, 8-12) and placed in a salient novel context or a similar context to the maternal cage. During PDs 15- 19 pups were tested in terms of ethanol orsaccharin consumption. All tests were conducted in the mentioned 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 PDs 18-19, two extinction sessions took place. Pups trained with ethanol under conditions that favour tolerance development, exhibited heightened ethanol consumption. Ethanoltreated animals underconditions that favour sensitization showed lower ethanol intake patterns. Ethanol preexposure, independently from conditions that favour tolerance or sensitization, was a significant factor leading to the inhibition of conditioned taste aversions. These results suggest that ethanol pre-exposure influencesethanol intake in a context-dependent manner and that ethanolmediated tasteaversions are reduced as a function of drug pre-exposure. The results suggest that ethanol-related early experiences sensitize the organism to the drug`s positive reinforcing effects and generates tolerance to its aversive unconditioned properties.