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

MARIA PAULA CORNEJO; MARIO PERELLO; NICOLAS DE FRANCESCO; FRANCO BARRILE

Congreso; XXXII Congreso Anual de la SAN; 2017

The ventral tegmental area (VTA) together with the nucleus accumbens (Acb) form the mesolimbic pathway and are involved in the regulation and processing of the rewarding aspects of food consumption. The VTA comprises different neuronal populations, with dopamine neurons being the most abundant and also gamma-aminobutyric acid (GABA) and glutamatergic neurons are present. 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 predominantly expressed in the brain and the VTA displays significant levels of this receptor. In this study, we investigated the ability of ghrelin to reach and induce an increase in c-Fos in VTA and Acb sub-divisions. We found that peripherally administered ghrelin fails to reach and activate VTA nor Acb neurons. We also found that centrally administered ghrelin is able to reach VTA neurons and induce an increase in c-Fos in different sub-divisions of the VTA and Acb. Finally, we show that dopaminergic neurons of the VTA fail to show an increase in 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 the population of VTA neurons that respond to ghrelin is distinct from dopaminergic neurons.