Nicotine improves working memory function in a variety of different testing situations. In a series of studies, we have found that chronic nicotine infusion improves working memory performance of rats in the win-shift version of the radial-arm maze. In the current studies, we examined the interaction of chronic nicotine effects in the radial-arm maze with dopamine D, agonist and antagonist drugs, since we have previously found significant interactions of acute nicotinic agonist and antagonist effects with D, systems. Replicating our earlier results, significant nicotineinduced improvements in working memory performance were seen. Chronic co-infusion of raclopride, a D, antagonist, or quinpirole, DJD, agonist, were not found to significantly interact with 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, systems with acute nicotine effects. Acute and chronic nicotine administration have similar effects of facilitating memory performance in the radial-arm maze. However, these effects appear to have differential interactions with D, systems. Drug Dev. Res. 39:29-35