Evidence that NPY Y1 receptors are involved in stimulation of feeding by orexins (hypocretins) in sated rats.
Regul Pept
; 87(1-3): 19-24, 2000 Feb 08.
Article
en En
| MEDLINE
| ID: mdl-10710284
ABSTRACT
Neuropeptide Y (NPY) produced in the arcuate nucleus (ARC) of the hypothalamus stimulates feeding both directly by activating NPY receptors and indirectly through release of the orexigenic peptides, galanin and beta-endorphin (beta-END), in the paraventricular nucleus (PVN) and surrounding neural sites. Orexin A and orexin B, produced outside the ARC in the lateral hypothalamic area (LH), have recently been shown to stimulate feeding. In the present studies we tested the hypothesis that NPYergic signaling may mediate feeding stimulated by orexins. In adult male rats injected intracerebroventricularly (i.c.v.) with orexin A (3, 10, 15 nmol) or orexin B (3, 10, 30 nmol) feeding was stimulated in a dose-dependent manner; maximal feeding was seen after 15 nmol orexin A and 30 nmol orexin B. To determine whether NPY may mediate this orexin stimulated feeding, we used 1229U91, a selective NPY Y1 receptor antagonist (NPY-A). Whereas NPY-A on its own was ineffective, it suppressed NPY-induced feeding. Furthermore, NPY-A completely blocked the feeding evoked by either orexin A (15 nmol) or orexin B (30 nmol). These results show that orexin A and B stimulate feeding and further suggest that these excitatory effects may be mediated by NPYergic signaling through Y1 receptors. These findings are in accord with the view that the orexin-NPY pathway may comprise a functional link upstream from NPY within the hypothalamic appetite regulating network.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neuropéptidos
/
Proteínas Portadoras
/
Receptores de Neuropéptido Y
/
Péptidos y Proteínas de Señalización Intracelular
/
Conducta Alimentaria
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Regul Pept
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos