CHARACTERIZATION OF GHRELIN-RESPONSIVE NEURONS OF THE LATERAL HYPOTHALAMIC AREA

BARRILE, FRANCO; CORNEJO, MARÍA PAULA; DE FRANCESCO, PABLO NICOLÁS; REYNALDO, MIRTA; PERELLÓ, MARIO

Villa Carlos Paz, Córdoba, Argentina

Congreso; XXXIV Reunión Anual SAN 2019; 2019

Sociedad Argentina de Investigación en Neurociencias

Lateral hypothalamic area (LHA) is a brain regioninvolved in the control of feeding, energy balance and motivated behavior,among other functions. LHA neurons express high levels of the ghrelin receptor(or, growth hormone secretagogue receptor, GHSR). Ghrelin is a stomach-derivedpeptide that regulates diverse functions exclusively via GHSR. In this study,we characterized GHSR neurons of the LHA. First, we mapped the distribution ofGHSR neurons of the LHA using mice in which the enhanced green fluorescentprotein (eGFP) is expressed under the control of the GHSR promoter (GHSR-eGFPmice). Then, we assessed the ability of GHSR neurons of the LHA to sensecentral or peripheral ghrelin by using a fluorescent ghrelin analog, and foundthat only centrally administered ghrelin reaches LHA cells. Also, we found thatGHSR neurons of the LHA increase the level of the marker of neuronal activationc-Fos in response to centrally injected ghrelin and fail to increase c-Fos inresponse to systemically injected ghrelin. We also found that GHSR neurons ofthe LHA do not express melanin concentrating hormone, orexin or the marker ofGABA cells Gad65. Moreover, intra-LHA ghrelin administration increases foodintake and locomotor activity. Thus, current data suggest that GHSR neurons ofthe LHA, whose phenotype remains unknown, could regulate some behavioralfunctions independently of plasma ghrelin levels.