CHRONIC NICOTINE-INDUCED IMPROVEMENT OF SPATIAL WORKING-MEMORY AND D-2 DOPAMINE EFFECTS IN RATS

Nicotine improves working memory function in a variety of different te sting situations. In a series of studies, we have found that chronic n icotine infusion improves working memory performance of rats in the wi n-shift version of the radial-arm maze. In the current studies, we exa mined the interaction of chronic nicotine effects in the radial-arm ma ze with dopamine D-2 agonist and antagonist drugs, since we have previ ously found significant interactions of acute nicotinic agonist and an tagonist effects with D-2 systems. Replicating our earlier results, si gnificant nicotine-induced improvements in working memory performance were seen. Chronic co-infusion of raclopride, a D-2 antagonist, or qui npirole, D-2/D-3 agonist, were not found to significantly interact wit h the choice accuracy improvement caused by nicotine. Acute challenge with a range of quinpirole doses also did not affect the facilitating effect of chronic nicotine. This stands in contrast to the significant interactions of D-2 systems with acute nicotine effects. Acute and ch ronic nicotine administration have similar effects of facilitating mem ory performance in the radial-arm maze. However, these effects appear to have differential interactions with D-2 systems. (C) 1997 Wiley-Lis s, Inc.