Do psychostimulant drugs really have aversive properties?

FERNÁNDEZ, G; REVILLO, D; PAGLINI, G; ARIAS C.

Huerta Grande

Congreso; XXVI Reunión Anual de la Sociedad Argentina de Neurociencias; 2011

Sociedad Argentina de Neurociencea

Psychostimulant drugs induce appetitive and aversive learning in rats. Their appetitive effects are more likely to become associated with contextual cues, while the aversive ones have been consistently found in taste aversion learning. To explain this paradox, it has been proposed that rats would avoid a taste that predicts a change in their homeostasis because this species cannot vomit. The goal of the present study was to assess the motivational properties of amphetamine by means of an odor conditioning preparation. The advantage of this procedure is that it enables the analysis of the hedonic value of the memory generated by means of a consumption test or in terms of locomotor approach to the odor. Results indicate that regardless the amphetamine dose (1 or 5 mg/Kg), when animals were evaluated in the intake test, subjects avoided the odor (Experiments 1a and 3a). However, the outcome in the locomotor avoidance test was modulated by the amphetamine dose. Rats trained with the low dose (1 mg/Kg) showed a preference towards the odor, while the highest amphetamine dose (5 mg/Kg) induced odor avoidance in this test (Experiment 3b). When LiCl was employed as a US, rats showed avoidance in the intake and locomotor activity tests. These results were discussed considering current theories of taste avoidance learning induced by rewarding drugs.