Neuroanatomical and functional characterization of the ghrelin-responsive neurons of the lateral hypothalamic area

BARRILE, FRANCO; CORNEJO, MARÍA PAULA; DE FRANCESCO, PABLO NICOLÁS; GARCÍA ROMERO, GUADALUPE; REYNALDO, MIRTA; PERELLO, MARIO

Córdoba, Argentina

Congreso; XXXIII CONGRESO ANUAL SAN 2018; 2018

Sociedad Argentina de Investigación en Neurociencias

Ghrelin is a stomach derived hormone thatregulates a variety of biological functions via the growth hormone secretagoguereceptor (GHSR), a receptor located in key brain areas that mediate the actionsof the hormone. GHSR is highly expressed in the lateral hypothalamic area(LHA), which controls essential functions, including food intake, locomotoractivity and reward-related behavioral responses. Here, we used a mouse model,in which the expression of enhanced green fluorescent protein (eGFP) iscontrolled by the promoter of GHSR (GHSR-eGFP mice), to gain neuroanatomicaland functional insights of the GHSR expressing neurons of the LHA. We foundthat GHSR neurons of the LHA are present from bregma -0.34 to bregma -2.70 inthe antero-posterior axis, and particularly enriched in the anterior (aLHA) andtuberal region (tLHA). GHSR neurons of the LHA increase the level of the markerof neuronal activation c-Fos in response to centrally injected ghrelin and failto increase c-Fos in response to systemically injected ghrelin. We also identifiedthat a subset of GHSR neurons of the LHA are GABAergic and that no GHSR neuronsof the LHA express orexin. Finally, we found that local intra-LHA rostralinfusions of ghrelin increase food intake. Thus, current data provide evidencethat ghrelin receptor signaling seems to target a subset of GABA neurons of theLHA that, in turn, affect food intake.