NMDA or 5-HT receptor antagonists impair memory reconsolidation and induce various types of amnesia

•NMDA or serotonin receptor antagonists paired with reminder-induced amnesia.•At an early (1 and 3 days) amnesia phase, the retraining was facilitated.•In the late phase (10 and 30 days), NMDA-dependent amnesia was resistant to retraining.•In the late phase, 5-HT-dependent amnesia retraining caused memory formation. Elucidation of amnesia mechanisms is one of the central problems in neuroscience with immense practical application. Previously, we found that conditioned food presentation combined with injection of a neurotransmitter receptor antagonist or protein synthesis inhibitor led to amnesia induction. In the present study, we investigated the time course and features of two amnesias: induced by impairment of memory reconsolidation using an NMDA glutamate receptor antagonist (MK-801) and a serotonin receptor antagonist (methiothepin, MET) on snails trained with food aversion conditioning. During the early period of amnesia (