The effects of receptor blockers on brain natriuretic peptide-32-induced action on passive avoidance behavior in rats.

The effects of several doses of porcine brain natriuretic peptide-32 (pBNP-32) administered into the lateral brain ventricle were tested as regards the consolidation of passive avoidance learning in rats. The peptide was found to increase the passive avoidance latency in a dose-dependent manner. In order to clarify which transmitter systems might be involved in the action of pBNP-32, the experimental animals were pretreated with different receptor blockers in selected doses which did not influence the behavioral paradigm. Four of the receptor blockers (haloperidol, atropine, phenoxybenzamine and propranolol) effectively blocked the action of the peptide on the consolidation of passive avoidance learning. The other three (naloxone, bicuculline and methysergide) were ineffective. The results suggest that dopaminergic, cholinergic and alpha- and beta-adrenergic mediations might be involved in the effects of pBNP-32 on the consolidation of passive avoidance learning in rats.