Orexins/hypocretins regulate drinking behaviour.
Orexin/hypocretins are recently identified neuropeptides which regulate feeding behaviour. We found orexins increased water intake when administrated intracerebroventricularly to rats. The effect of orexin-A was more potent as compared with orexin-B, suggesting the possible involvement of OX(1) receptor. The efficacy of orexin-A was almost comparable with that of angiotensin II, and the effect lasted more than 3 h. Prepro-orexin mRNA level was up-regulated when rats were deprived of water. Orexin-immunoreactive varicose axons were observed in the subfornical organ and area postrema, regions implicated in drinking behaviour. These observations suggest a physiological role for orexin as mediators that regulate drinking behaviour.
Kunii
K
K
Department of Pharmacology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, Japan.
Yamanaka
A
A
Nambu
T
T
Matsuzaki
I
I
Goto
K
K
Sakurai
T
T
D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000096:biosynthesis / Q000502:physiology*; D002552:Cerebral Ventricles / Q000378:metabolism; D004327:Drinking Behavior / Q000502:physiology*; D007026:Hypothalamic Area, Lateral / Q000378:metabolism / Q000502:physiology; D007150:Immunohistochemistry; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D009479:Neuropeptides / Q000096:biosynthesis / Q000502:physiology*; D000068797:Orexins; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D013268:Stimulation, Chemical; D020530:Subthalamus / Q000378:metabolism / Q000502:physiology; D015854:Up-Regulation / Q000187:drug effects; D014868:Water Deprivation / Q000502:physiology
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D012333:RNA, Messenger; D000804:Angiotensin II