Ghrelin increses glutamate release from rats hippocampal synaptosomes.

MARISA GHERSI,; BUTELER FLORENCIA; VILCAES ALEJANDRO; SUSANA RUBIALES DE BARIOGLIO,

Huerta Grande -Cordoba

Congreso; XXVI Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia (SAN); 2011

SAN

Ghrelin increases glutamate release from rats hippocampal synaptosomes. Marisa Ghersi1, Florencia Buteler1, Alejandro Vilcaes2 and Susana R. de Barioglio1. 1Dpto. de Farmacología Facultad de Ciencias Químicas, UNC, (IFEC-CONICET), Argentina 2Dpto. de Química Biológica Facultad de Ciencias Químicas, UNC Ghrelin (Ghr) is a peptide that participates in the modulation of different biological processes. In our laboratory we have shown that Ghr modulated memory acquisition and consolidation; intra-hippocampal Ghr administration increased the nitric oxide synthase (NOS) activity in a dose dependent manner, and reduced the threshold for LTP generation in dentate gyrus. The biochemical memory cascade is initiated by the glutamate (Glu) release followed by the activation of AMPA and NMDA receptors, increasing [Ca2+]i, NOS activity and GMPc levels. The possible mechanisms underlying the Ghr-facilitatory effect on memory have not been clarified. NO enhances the Glu release and this evoked release is important to LTP. In the present work we studied, the effect of Ghr on Glu release using an in vitro preparation of rat hippocampal synaptosomes incubated in the presence of Ghr. Glu was monitored fluorometrically. Data points were obtained at 1-s intervals during 20 min. Results are expressed as % of change in Glu release in relation to the control group. The addition of Ghr to the medium increases Glu release reaching 30% with the dose of 0.03 nM. In conclusion, results provide additional evidence about the neurobiological bases of Ghr action in hippocampus