Amnesia by inhibition of dorsal hippocampus protein synthesis or NMDA receptors is overcome by previous OF exploration

SNITCOFSKY MARINA; COLETTIS NATALIA; KORNISIUK EDGAR; JERUSALINSKY DIANA

Huerta Grande, Córdoba

Congreso; XXVI Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias; 2011

SAN - Sociedad Argentina de Investigación en Neurociencias

To further investigate the participation of hippocampal protein synthesis and NMDA receptors (R) in memory formation, we trained rats in a one-step inhibitory avoidance (IA) task: when stepping-down from an isolated platform onto a grid-floor they got a 0.5 mA footshock; latencies to step-down in training and test session, performed 24 h later, were recorded. Rats were injected intrahippocampus with the protein synthesis inhibitors Anysomicin or Cicloheximide (8 μg/side) 120 min before IA training, leading to anterograde amnesia. The NMDAR antagonist MK801 (2μg/side) was injected immediately after IA training, leading to retrograde amnesia. Other rats were let to explore twice an open field (OF) for 3 min, 24 h and 90 min before IA training, showing habituation to the arena. Although they received the drugs according to a similar protocol, these animals were able to express a conspicuous long term memory of IA. Our results corroborate the amnesic effects of the three drugs, but revealed that the previous exploration/ habituation to the arena allowed to overcome the amnesia, raising questions about dorsal hippocampus protein synthesis as unique source of synaptic plasticity proteins for this aversive memory formation, and the hippocampal NMDAR involvement there.