| Abstract: | Five experiments investigated in rats the effects of increasing or decreasing plasma corticosterone levels on schedule-induced polydipsia (SIP) and dopamine efflux in the nucleus accumbens. The results indicate that the acquisition of SIP could be decreased by adrenalectomy, blockade of corticosterone synthesis, or administration of corticosterone. Performance of established SIP was also decreased by adrenalectomy. The effects of corticosterone administration on established SIP depended on the level of performance. High levels of drinking were enhanced by a high dose of corticosterone, whereas low rates of drinking were increased by a low dose. Similar injections of corticosterone also significantly increased dopamine efflux. The relative involvement of pituitary–adrenal activity and dopamine neurotransmission to the nucleus accumbens in the acquisition and performance of SIP is discussed and related to contemporary hypotheses of schedule-induced behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
