Ghrelin increases learning consolidation and facilitates synaptic plasticity through mechanisms dependent on NR2B subunits of the NMDA receptor Susana.

BUTELER FLORENCIA; GHERSI M,; GABACH L,; MARIELA PEREZ; RUBIALES SUSANA DE BARIOGLIO

Valle Hermoso -Cordoba

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

SAN

Ghrelin (Ghr) is a peptide synthesized both peripherally and in the central nervous system that participates in feeding control and learning and memory. Ghr receptors are expressed in the hypothalamus and in other brain structures such as the hippocampus (Hi), a structure involved in learning and memory processes. The biochemical cascade of memory as well as Hi long term potentiation (LTP) involve the stimulation of glutamatergic receptors (AMPA and NMDA). 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 in rats enhances memory consolidation in the step-down test (SDT) and reduces the threshold to induce LTP in Hi. However, the molecular and cellular basis of Ghr effects still remains unclear. In the present work we studied the participation of NMDAR containing NR2B subunits in the Ghr effect using a SDT and electrophysiological recordings. Our results showed that intra-Hi administration of a selective NR2B antagonist (Ro-256981) previous to Ghr partially blocked memory consolidation and increased threshold to generate Hi LTP in relation to Ghr alone suggesting that Ghr effects were partially dependent on NR2B subunit.