Ghrelin Signaling Targets Segregated Clusters of Neurons Within the Nucleus of the Solitary Tract

CORNEJO MP , DE FRANCESCO PN , GARCIA ROMERO G , PORTIANSKY EL , ZIGMAN JM , REYNALDO M , PERELLO M .

San Diego

Congreso; SFN Meeting; 2018

Society for Neuroscience

Ghrelin is a stomach-derived peptidic hormone that acts through its G protein-coupled receptor named the growth hormone secretagogue receptor (GHSR). Ghrelin acts in the central nervous system to regulate a variety of functions including food intake, blood glucose homeostasis and gastrointestinal motility, among others. The neuroanatomical distribution of GHSR in the mouse brain is wellestablished, and some neuronal targets of ghrelin have been linked to specific actions of the hormone. GHSR neurons are present in the dorsal vagal complex, which is a structure located in the medulla oblongata and includes the nucleus of the solitary tract (NTS) and the area postrema (AP). These two nuclei control many essential functions including orofacial, autonomic, neuroendocrine and behavioral responses. The distribution, chemical phenotype and function of NTS GHSR neurons have been only rudimentarily described or theorized in the past. Thus, the current study was performed in order to gain neuroanatomical and functional insights of NTS GHSR neurons. We used different approaches, including transgenic mice, stereotaxic surgeries and behavioral tests in order toinvestigate the distribution, chemical phenotype and function of the NTS GHSR neurons. Based on the results shown in this poster, we conclude that:→GHSR expressing neurons are distributed along the antero-posterior extension of the NTS forming two groups of clusters.→GHSR expressing neurons are concentrated in specific subdivisions of the NTS and a subset of them are GABAneurons.→GHSR expressing neurons of the rostral NTS are activated when hyperphagic events occur, while GHSR expressing neurons of the caudal are activated by sensory inputs from the gastrointestinal tract.According to the results shown in this poster and previous data published in Cabral et al., 2017, we propose the following functions for the ghrelin/GHSR system acting at the dorsal vagal complex.