Abstract
The effects of i.c.v. administration of orexin/hypocretin on plasma ACTH, corticosterone and c-fos mRNA in the paraventricular nucleus (PVN) of the rat were examined. Plasma ACTH levels were markedly increased at 30 min after i.c.v. administration of orexin-A. Plasma corticosterone levels were significantly increased in a dose-related manner 30 min after i.c.v. administration of orexin-A and orexin-B. In situ hybridization histochemistry revealed that the induction of the c-fos mRNA in the parvocellular division of the PVN was increased in a dose-related manner 30 min after i.c.v. administration of orexin-A and orexin-B. These results suggest that central orexin/hypocretin activates hypothalamo-pituitary-adrenal (HPA) axis and may be involved in stress-induced activation of the HPA axis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adrenocorticotropic Hormone / blood
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Animals
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Carrier Proteins / administration & dosage*
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Carrier Proteins / pharmacology
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Corticosterone / blood
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Gene Expression / drug effects
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Genes, fos
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Histocytochemistry
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Hypothalamo-Hypophyseal System / drug effects*
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In Situ Hybridization
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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 / administration & dosage*
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Neuropeptides / pharmacology
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Orexins
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Osmolar Concentration
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Paraventricular Hypothalamic Nucleus / metabolism
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Pituitary-Adrenal System / drug effects*
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RNA, Messenger / metabolism
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Rats
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Rats, Wistar
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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Adrenocorticotropic Hormone
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Corticosterone