Centrally administered ghrelin potently inhibits water intake induced by angiotensin II and hypovolemia in rats.
Ghrelin is a potent, centrally acting orexigenic hormone. Recently, we showed that centrally administered ghrelin is a potent antidipsogenic hormone in 24-h water deprived rats. In this study, we examined the effect of intracerebroventricular (icv) injection of ghrelin on angiotensin II (AII)-induced water intake in rats. We also examined the effects of icv injection of ghrelin on drinking induced by intraperitoneal injection of an isotonic polyethylene glycol (PEG) solution that causes isotonic hypovolemia. Water intake induced by the icv injection of AII or ip injection of PEG was significantly reduced after icv injection of ghrelin, although food intake was stimulated by the hormone. The drinking induced by AII was also inhibited by the icv administration of 4alpha-phorbol 12, 13-didecanoate, an agonist of the osmosensitive TRPV4 channel. This study showed that ghrelin is a potent antidipsogenic peptide by antagonizing general dipsogenic mechanisms including those activated by AII and hypovolemia in rats.
Hashimoto
Hirofumi
H
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Otsubo
Hiroki
H
Fujihara
Hiroaki
H
Suzuki
Hitoshi
H
Ohbuchi
Toyoaki
T
Yokoyama
Toru
T
Takei
Yoshio
Y
Ueta
Yoichi
Y
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects*; D004435:Eating / Q000187:drug effects; D054439:Ghrelin / Q000008:administration & dosage* / Q000494:pharmacology; D020896:Hypovolemia / Q000503:physiopathology*; D007276:Injections, Intraventricular; D008297:Male; D010704:Phorbols / Q000008:administration & dosage / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats; D050916:TRPV Cation Channels / Q000819:agonists
C517592:4alpha-phorbol 12,13-didecanone; D054439:Ghrelin; D010704:Phorbols; D050916:TRPV Cation Channels; C486577:Trpv4 protein, rat; C422650:ghrelin, des-n-octanoyl; D000804:Angiotensin II; D011092:Polyethylene Glycols