Physiological and environmental aspects of drinking stimulated by chronic exposure to amphetamine in rats.

1. To examine whether the hyperdipsic response to chronic administration of d,l-amphetamine (AMPH) is associated with modification of salt appetite, rats were allowed to choose between tap water and a 1.7% NaCl solution. 2. Under AMPH rats preferred water to saline throughout the experiment. 3. By testing rats in a distinct test cage environmental influences on AMPH-mediated hyperdipsia were also evaluated. 4. In the test cage hyperdipsia was suppressed, but preference for tap water was preserved. 5. Finally, the role of alpha 2-adrenoceptors in the drinking response to AMPH was evaluated by studying the effects of clonidine and yohimbine on water intake. 6. We conclude that AMPH-induced preference for tap water over saline is unrelated to hyperdipsia but, being also induced by yohimbine, it may depend on noradrenergic mechanisms.