Ghrelin induced memory facilitation implicates Nitric oxide synthase activation and decrease in the threshold to promote LTP in hippocampal dentate gyrus.

VALERIA P CARLINI; MARIELA F. PÉREZ.; ESTELA SALDE; SCHIÖTH, HELGI; OSCAR A. RAMÍREZ; SUSANA R BARIOGLIO

PHYSIOLOGY AND BEHAVIOR

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2010 vol. 101 p. 117 - 117

0031-9384

lthough the hypothalamus has been long considered the main ghrelin (Ghr) target organ mediating orexigenic effects, recently it has been shown that in-vivo Ghr hippocampus administration improves learning and memory in the inhibitory avoidance paradigm. However, the possible mechanisms underlying this memory facilitation effect have not been clarified. Given that the biochemical memory cascade into the hippocampus involves nitric oxide (NO) synthesis via NO synthase (NOS) activation, we investigated 1) if Ghr administration modulated NOS activity in the hippocampus; and 2) if hippocampal NOS inhibition influenced Ghr-induced memory facilitation, using a behavioral paradigm, biochemical determinations and an electrophysiological model. Our results showed that intra-hippocampal Ghr administration increased the NOS activity in a dose dependent manner, and reduced the threshold for LTP generation in dentate gyrus of rat hippocampus. Moreover, pre-administration of NG-nitro-L-arginine (L-N