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.