INVESTIGADORES
DE FRANCESCO Pablo Nicolas
congresos y reuniones científicas
Título:
Hypothalamic tanycytes mediate ghrelin uptake into brain tissue
Autor/es:
FERNÁNDEZ G; FRASSA M V; DE FRANCESCO P N; CABRAL A; CASTROGIOVANNI D; PORTIANSKY E L; PERELLÓ M
Lugar:
Huerta Grande, Córdoba
Reunión:
Congreso; XXIX CONGRESO ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACION EN NEUROCIENCIAS; 2014
Institución organizadora:
Sociedad Argentina de Investigación en Neurociencias
Resumen:
Ghrelin is a stomach-derived hormone that acts in the
brain to regulate food intake, stress, and glucose homeostasis. Small doses of
peripherally administrated ghrelin mainly activate neurons in the hypothalamic
arcuate nucleus; however, higher doses also activate neurons in dorsal
periventricular hypothalamic sites suggesting the passage of ghrelin from the
periphery to the cerebrospinal fluid (CSF).
Tanycytes are highly specialized ependymal cells that
form a blood?cerebrospinal fluid barrier at the level of the median
eminence/arcuate nucleus. Recently, it has been proposed that tanycytes could
transport hormones from the blood to the CSF.
Here, we hypothesize that tanycytes are able to
perform ghrelin uptake from either the periphery and/or the CSF. In order to
test this possibility, we centrally injected mice and rats with fluorescent
ghrelin and mapped its localization in the ependymal and periventricular
hypothalamic areas. In addition, we developed an in vitro model of primary
cultures enriched in tanycytes.
We found that hypothalamic tanycytes are able to
incorporate ghrelin injected centrally from the third ventricle to the
hypothalamic parenchyma. In the in vitro system, we detected tanycytes-like
cells, which were immuno-reactive for vimentin and incorporated fluorescein
ghrelin tracer added to the culture media.
We conclude that
hypothalamic tanycytes could be an important physiological checkpoint
regulating the hypothalamic actions of ghrelin.