[Protein synthesis is necessary for induction of amnesia, elicited by disruption of long-term memory reconsolidation].

The NMDA glutamate receptor antagonists (MK-801 or APV) as well as protein synthesis inhibitors (cycloheximide or anisomycine) affect reactivation processes of long-term memory as studied in snail Helix lucorum with food aversion conditioning. It was found that, 24 hours after training, injection of each of the above mentioned substances initiated amnesia with duration more than 3 weeks. Repeated aversion conditioning with the same food (as at initial one) produced no memory restoration. However, amnesia was not observed in snails after simultaneous injection of protein synthesis inhibitor and NMDA glutamate receptor antagonists (MK-801 + cycloheximide or APV + anisomycin) before reminding procedure. In next experiments, cycloheximide was injected 3-9 hours after MK-801/reminding procedure. We have found development of incomplete amnesia in snails with cycloheximide injection 3 or 6 hours after MK-801/reminding procedure and, at repeated aversion conditioning with the same food, memory was quickly restored. Cycloheximide injection 9 hours after MK-801/reminding procedure led to development ofa steady-state amnesia with disruption of aversion conditioning with the same food as at repeated training. We suggest that mechanisms of "MK-801-induced amnesia" (as well as other mechanisms of long-term adaptive processes in the brain) depend on novel protein synthesis and become suppressed after inhibitors of protein synthesis application. "Time window" of amnesia induction process dependence on protein molecules synthesis remains during 6-9 hours after MK-801/reminding procedure.