Spatial working memory is independent of hippocampal CA1 long-term potentiation in rats

This study investigated the relationship between spatial working memory and hippocampal long-term potentiation (LTP) using the allocentric place discr imination task (APDT) in rats, in which the selection accuracy is a good in dex for spatial working memory. Either the selective M1 muscarinic receptor antagonist pirenzepine (50 mu g) or the choline uptake inhibitor hemicholi nium-3 (5 mu g) impaired APDT selection accuracy, but neither affected the induction of LTP in the hippocampal CA1 region in anesthetized rats. In con trast, the selective N-methyl-D-aspartate receptor antagonist D-amino-5-pho sphonopentanoate (200 nmol) did not impair APDT selection accuracy but comp letely blocked hippocampal CA1 LTP. These results suggest that spatial work ing memory is independent of hippocampal CA1 LTP and that the central choli nergic system is involved in spatial working memory, but not through the mo dulation of hippocampal CA1 LTP.