Intraventricular galanin impairs delayed nonmatching-to-sample performance in rats.

Galanin is a neuroactive peptide that coexists with acetylcholine in the basal forebrain region. Galanin inhibits cholinergic functions in vitro and in vivo and has been shown to impair performance in some memory tasks. The present study compared the effects of galanin with the effects of scopolamine (a muscarinic antagonist) and ketamine and MK-801 (both NMDA receptor antagonists) on performance of an operant, spatial, delayed nonmatching-to-sample task in rats. Choice accuracy was impaired in a dose-dependent but delay-independent manner by galanin, scopolamine, and MK-801 but was not systematically influenced by ketamine. Measures of session duration, trials completed, discrimination accuracy, preservation, within-trial error distribution, and operant lever pressing were also analyzed. These results support observations that galanin disrupts performance in memory tasks requiring delayed responding but that the disruption is not specific to mnemonic capabilities.