NMDA receptor subunits involvement in memory formation of hippocampus-dependent tasks

SNITCOFSKY M; BAEZ MV; COLETTIS N; AGUIRRE AI; CERCATO MC; CHELI VT; JERUSALINSKY DA

Huerta Grande

Congreso; XXVII Reunión Anual Sociedad Argentina de Investigación en Neurociencias.; 2012

Sociedad Argentina de Investigación en Neurociencias (SAN)

Hippocampal NMDA receptors (NMDAR) are required to consolidate inhibitory avoidance (IA) and open field (OF) memory in rats, since the administration of MK-801 immediately after training leads to amnesia. Most hippocampal NMDAR contain GluN2A or GluN2B subunits. The selective GluN2B antagonist Ifenprodil administered intra-hippocampus immediately after training, allowed long-term memory (LTM) formation of IA with a subthreshold training, facilitated memory of IA when training was just overtreshold and of an object location task. These results indicate that GluN2B-containing NMDAR negatively modulate memory consolidation. On the other hand, habituation to an OF was not affected by ifenprodil injected intrahippocampus right after the first session, suggesting that it does not depend on GluN2B containing receptors. Hippocampal proteins obtained 30 and 70 minutes after rat exposure to a 5 minutes OF session ? which leads to recognition and habituation to the field - were analyzed by westernblot for NMDAR subunits. While GluN1 and GluN2A significantly increased at 70 min, GluN2B did not. Our results show that NMDAR subunits actively and selectively change during OF consolidation, in a similar way to the changes reported to occur after LTP induction (see Cercato et al; Aguirre et al, 2012). These changes, along with the above reported behavioral data, suggest that GluN2A rather than GluN2B would participate in the OF memory (spatial habituation) processing.