title: Enhanced effect of neuropeptide Y on food intake caused by blockade of the V(1A) vasopressin receptor.
abstract: Food intake is regulated by various factors such as neuropeptide Y. Neuropeptide Y potently induces an increase in food intake, and simultaneously stimulates arginine-vasopressin (AVP) secretion in the brain. Recently, we reported that V(1A) vasopressin receptor-deficient (V(1A)R(-/-)) mice exhibited altered daily food intake accompanied with hyperglycemia and hyperleptinemia. Here, we further study the involvement of the AVP/V(1A) receptor in the appetite regulation of neuropeptide Y with V(1A)R(-/-) mice and antagonists for the AVP receptor. The intra-cerebral-ventricle administration of neuropeptide Y induced greater food consumption in V(1A)R(-/-) mice than wild-type (WT) mice, whereas an anorexigenic effect of leptin was not different between the two groups. This finding suggests that the orexigenic effect of neuropeptide Y was enhanced in V(1A)R(-/-) mice, leading to the increased food intake in response to the neuropeptide Y stimulation. In addition, the neuropeptide Y-induced orexigenic effect was enhanced by co-administration of OPC-21268, an antagonist for the V(1A) vasopressin receptor, into the cerebral ventricle in WT mice, whereas the neuropeptide Y-induced orexigenic effect was not affected by co-administration of SSR-149415, an antagonist for the V(1B) vasopressin receptor. These results indicate that AVP could suppress the neuropeptide Y-induced orexigenic effect via the V(1A) vasopressin receptor, and that blockade or inhibition of the AVP/V(1A) receptor signal resulted in the enhanced neuropeptide Y-induced orexigenic effect. Thus, we show that the AVP/V(1A) receptor is involved in appetite regulation as an anorexigenic factor for the neuropeptide Y-induced orexigenic effect.
authors.affiliation: Department of Pharmacology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, Japan. toshinori.aoyagi@hsc.utah.edu
authors.forename: Toshinori
authors.initials: T
authors.lastname: Aoyagi
authors.forename: Shinji
authors.initials: S
authors.lastname: Kusakawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sanbe
authors.forename: Masami
authors.initials: M
authors.lastname: Hiroyama
authors.forename: Yoko
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Junji
authors.initials: J
authors.lastname: Yamauchi
authors.forename: Akito
authors.initials: A
authors.lastname: Tanoue
mesh_terms: D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001066:Appetite / Q000187:drug effects; D001127:Arginine Vasopressin / Q000378:metabolism / Q000494:pharmacology; D004435:Eating / Q000187:drug effects*; D005247:Feeding Behavior / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009478:Neuropeptide Y / Q000494:pharmacology*; D017483:Receptors, Vasopressin / Q000172:deficiency / Q000378:metabolism
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D009478:Neuropeptide Y; D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin