HALOPERIDOL-INDUCED BLOCKADE OF INDUCTION OF LONG-TERM POTENTIATION IN PERFORANT PATH-DENTATE GYRUS PATHWAY IN CHRONICALLY PREPARED RABBITS

We investigated the effects of the representative neuroleptic and dopa mine receptor antagonist haloperidol (HPD) on the induction of long-te rm potentiation (LTP) or on the previously induced LTP in the perforan t path-dentate gyrus pathway in chronically prepared rabbits. The IP H PD injection of 0.8 mg/kg blocked the induction of LTP when it was giv en before LTP-inducing tetanic stimulations, although this dose showed virtually no effect on the baseline control responses in the perforan t path-dentate gyrus pathway to single shocks. However, neither 0.8-mg /kg nor 1.6-mg/kg HPD doses affected the previously induced LTP. The p ossible mechanisms underlying these results, notably the HPD-induced b lockade of LTP induction, are discussed, especially in association wit h the inhibitory action of HPD on calmodulin-mediated events rather th an dopaminergic function.