Haloperidol-induced blockade of induction of long-term potentiation in perforant path-dentate gyrus pathway in chronically prepared rabbits

Abstract

We investigated the effects of the representative neuroleptic and dopamine receptor antagonist haloperidol (HPD) on the induction of long-term potentiation (LTP) or on the previously induced LTP in the perforant path-dentate gyrus pathway in chronically prepared rabbits. The IP HPD injection of 0.8 mg/kg blocked the induction of LTP when it was given before LTP-inducing tetanic stimulations, although this dose showed virtually no effect on the baseline control responses in the perforant path-dantate gyrus pathway to single shocks. However, neither 0.8-mg/kg nor 1.6-mg/kg HPD doses affected the previously induced LTP. The possible mechanisms underlying these results, notably the HPD-induced blockade of LTP induction, are discussed, especially in association with the inhibitory action of HPD on calmodulin-mediated events rather than dopaminergic function.