Ghrelin Uptake By The Blood-Cerebrospinal Fluid Barrier Occurs In A Ghrelin Receptor-Independent Manner

MAIA URIARTE; GIMENA FERNANDEZ; PABLO N. DE FRANCESCO; DANIELA LUFRANO; AGUSTINA CABRAL; MARIO PERELLÓ

Congreso; Sociedad Argentina de Investigación en Neurociencias, XXX Annual Meeting; 2015

Ghrelin is a 28-amino acid octanoylated peptide hormone secreted from the stomach. Ithas been suggested that one of the mechanisms by which ghrelin reaches the braininvolves crossing the blood-cerebrospinal fluid barrier at either the choroids plexus and/orthe hypothalamic tanycytes that line the floor of the third ventricle. However, themechanisms mediating the transport of ghrelin into the brain are currently unknown. Thegoal of this study was to get insights into the system mediating ghrelin uptake at the bloodcerebrospinal fluid barrier. We found that both the ependymal cells of the choroids plexusand the hypothalamic tanycytes display fluorescent-ghrelin tracer uptake in vivo.Interestingly, we failed to find ghrelin receptor gene expression within these cell types oran increase of pERK levels, a downstream target of ghrelin receptor signaling, by ghrelin orthe fluorescent-ghrelin tracer. In addition, we found that ependymal cells of the choroidsplexus and the hypothalamic tanycytes of a ghrelin receptor deficient mice show similarpatterns of tracer uptake as seem in wild type mice. Thus, we conclude that ghrelin uptakein the blood-cerebro spinal barrier occurs in a ghrelin receptor-independent fashion.Supported by PICT2011-2142, PICTO2013-0065 and 11/X605.