Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Angiotensin II / administration & dosage
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Angiotensin II / pharmacology
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Animals
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Blotting, Northern
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Carrier Proteins / biosynthesis
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Carrier Proteins / physiology*
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Cerebral Ventricles / metabolism
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Drinking Behavior / physiology*
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Hypothalamic Area, Lateral / metabolism
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Hypothalamic Area, Lateral / physiology
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Immunohistochemistry
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Injections, Intraventricular
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Intracellular Signaling Peptides and Proteins*
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Male
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Neuropeptides / biosynthesis
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Neuropeptides / physiology*
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Orexins
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RNA, Messenger / biosynthesis
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Rats
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Rats, Wistar
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Stimulation, Chemical
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Subthalamus / metabolism
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Subthalamus / physiology
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Up-Regulation / drug effects
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Water Deprivation / physiology
Substances
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Carrier Proteins
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Intracellular Signaling Peptides and Proteins
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Neuropeptides
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Orexins
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RNA, Messenger
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Angiotensin II