Circulating or cerebrospinal fluid ghrelin regulates different neuronal circuits within the dorsal vagal complex

CORNEJO MP; CABRAL A; DE FRANCESCO PN; FERNANDEZ G; VALDIVIA S; GARCIA ROMERO G; REYNALDO M; PERELLO M

La Falda

Congreso; XXIX Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia; 2014

Sociedad Argentina de Investigación en Neurociencia

The dorsal vagal complex (DVC) of the brainstem includes the nucleus of the solitary tract (NTS), the area postrema (AP), and the dorsal motor nucleus of the vagus (10N). The DVC is an integrative center that regulates food intake and also relays autonomic neural circuits that control many key functions including blood glucose concentration, blood pressure, gastro-intestinal motility, among others. The growth hormone secretagogue receptor (GHSR), which is the target of the hormone ghrelin, is expressed in the DVC. Given the technical difficulties to identify GHSR by traditional techniques, the detailed neuroanatomical distribution of GHSR-expressing neurons within the DVC and the physiological role of ghrelin signaling on this brain area are unclear.In the current study, we performed a detailed neuroanatomical characterization of the distribution of GHSR within the DVC using a transgenic mice in which the green fluorescent protein (GFP) is under the control of the GHSR promoter (GHSR-GFP mice). Also, we performed immunohistochemistry (IHC) with markers of specific neuronal populations in order to characterize the phenotype of the GHSR-expressing neurons. Finally, we used fluorescein-ghrelin (F-ghrelin, as a tracer peptide) and the marker of cellular activation c-Fos to study the responsiveness of GHSR-expressing neurons of the DVC to ghrelin.