Centrally administered orexin/hypocretin activates HPA axis in rats.
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.
Kuru
M
M
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Ueta
Y
Y
Serino
R
R
Nakazato
M
M
Yamamoto
Y
Y
Shibuya
I
I
Yamashita
H
H
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D002352:Carrier Proteins / Q000008:administration & dosage* / Q000494:pharmacology; D003345:Corticosterone / Q000097:blood; D015870:Gene Expression / Q000187:drug effects; D016762:Genes, fos; D006651:Histocytochemistry; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects*; D017403:In Situ Hybridization; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D009479:Neuropeptides / Q000008:administration & dosage* / Q000494:pharmacology; D000068797:Orexins; D009994:Osmolar Concentration; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D012333:RNA, Messenger; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone