GHRELIN INCREASES LEARNING CONSOLIDATION AND FACILITATES SYNAPTIC PLASTICITY THROUGH MECHANISMS DEPENDENT ON NR2B SUBUNITS OF THE NMDA RECEPTOR.

BUTELER F*; GHERSI M*; GABACH L; PEREZ M; DE BARIOGLIO SR

Huerta Grande, Córdoba

Congreso; XXVII Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia (SAN); 2012

SAN

Ghrelin (Ghr) is a peptide synthesized both peripherally and in the centralnervous system that participates in feeding control and learning and memory.Ghr receptors are expressed in the hypothalamus and in other brain structuressuch as the hippocampus (Hi), a structure involved in learning and memoryprocesses. The biochemical cascade of memory as well as Hi long termpotentiation (LTP) involve the stimulation of glutamatergic receptors (AMPA andNMDA). Furthermore, a critical requirement of NMDA receptor (NMDAR)containing NR2B subunits for the induction of LTP has been demonstrated.Previously in our laboratory we demonstrated that intra-Hi Ghr administration inrats enhances memory consolidation in the step-down test (SDT) and reducesthe threshold to induce LTP in Hi. However, the molecular and cellular basis ofGhr effects still remains unclear. In the present work we studied theparticipation of NMDAR containing NR2B subunits in the Ghr effect using a SDTand electrophysiological recordings. Our results showed that intra-Hiadministration of a selective NR2B antagonist (Ro-256981) previous to Ghrpartially blocked memory consolidation and increased threshold to generate HiLTP in relation to Ghr alone suggesting that Ghr effects were partiallydependent on NR2B subunit.