Effect of amygdaloid lesions on ethanol intake in rats

The effect of electrolytic lesions of the amygdala on ethanol intake in ethanol naïve rats has been studied. Rats with basolateral nuclei and lateral nuclei lesions showed a reduced neophobic response to an ethanol solution. However, the ethanol intake was too small in normal and lesioned rats to augment aversion through conditioning. Oral intake of ethanol supplemented by intraperitoneal ethanol injection to reach 2 g/kg indeed enhanced the initial sensory aversion to ethanol. This induced aversion was attenuated after basolateral lesions. An initial aversion to a mixed ethanol-sucrose solution was abolished after basolateral lesions, while the lateral lesions induced an initial preference for this solution. The initial oral intake of ethanol-sucrose in normal rats was again too small to induce the conditioned taste aversion (C.T.A.). Despite the high oral intake of this solution, rats with basolateral lesions did not show a conditioned aversion while laterally lesioned rats exhibited a strong conditioned aversion to the ethanol-sucrose mixture. The results which confirm the suppression of the C.T.A. by basolateral amygdala lesions are discussed in relation to the role of toxicophobia in ethanol intake by rats.