Involvement of neurotransmitters in the action of growth hormone-releasing hormone antagonist on passive avoidance learning

► The involvement of transmitters in the passive avoidance learning of MZ-4-71, a GH-RH antagonist, has been tested. ► In the experiments the animals were pretreated with adrenergic, cholinergic, serotonergic, dopaminergic, opiate and GABA-A antagonists. ► The cholinergic, 5HT1/5HT2 serotonergic and opiate receptor antagonists blocked the memory consolidating action of MZ-4-71.