Effects of lesions in the basolateral amygdala on fluid intake in the rat.

Drinking response to hypertonio saline, a cellular thirst stimulus, and to isoproterenol, probably an extracellular thirst stimulus, was normal in rats with bilateral lesions in the basolateral region of the amygdala. The overnight water intake of the lesioned rats was a little higher than normal. However, the lesioned rats showed a major impairment in learning to avoid ingesting a poisonous solution of LiCl when they were thirsty. The lesioned rats also showed an increased preference of 25% sucrose in a two-bottle sucrose-water test. The main conclusion is that the basolateral region of the amygdala is involved in the effects of previous experience on drinking and not primarily in the cellular or extracellular controls of drinking.