GHRELIN SIGNALING DIFERENTIALLY ACTIVATES NON-DOPAMINERGIC NEURONS OF THE VENTRAL TEGMENTAL AREA SUBREGIONS

CORNEJO MP; BARRILE F; DE FRANCESCO PN; PERELLO M

Mar Del Plata

Congreso; XXXII Reunión Anual de la Sociedad Argentina de Neurociencias; 2017

Sociedad Argentina de Investigación en Neurociencias

The ventral tegmental area (VTA) together with the nucleus accumbens (Acb) form the mesolimbic pathway, which is involved in the regulation and processing of the rewarding aspects of food consumption. The VTA comprises different neuronal populations, including dopaminergic, GABAergic and glutamatergic neurons. The VTA and Acb are both divided in three different sub-divisions with differential connectivity. Ghrelin is a peptidic orexigenic hormone secreted from stomach that binds to a G-protein coupled receptor, the growth hormone secretagogue receptor (GHSR). GHSR is expressed in several brain nuclei involved in food intake regulation, including the VTA. In this study, we investigated the ability of ghrelin to reach and activate VTA and Acb sub-divisions. We found that peripherally administered ghrelin fails to reach and increase the levels of the marker of neuronal activation c-Fos in both the VTA and the Acb. We also found that centrally administered ghrelin reaches VTA neurons and increases c-Fos in different sub-divisions of the VTA and Acb. Finally, we show that dopaminergic neurons of the VTA fail to increase c-Fos in response to centrally administered ghrelin. Thereby, we conclude that central ghrelin is able to reach the VTA and to activate VTA and Acb sub-divisions, and that VTA neurons activated by ghrelin are not dopaminergic neurons.