The effect of orexin-A and -B on the histamine release in the anterior hypothalamus in rats.
The neuropeptides orexin-A and -B have been reported to be appetite-stimulating peptides, but they are also known as important factors that control arousal state. We studied the effects of orexin-A and -B on the hypothalamic histamine release using in vivo microdialysis. A significant and sustained increase in histamine release was observed by intracerebroventricular injection of 1 nmol of orexin-A, but not by the same dose of orexin-B. An increased dose of orexin-B to 5 nmol facilitated histamine release, although this effect was much less potent than orexin-A. These findings suggest that both of the orexins play important roles in the regulation of waking through the activation of histaminergic system.
Ishizuka
Tomoko
T
Department of Medical Physics, School of Allied Health Sciences, Faculty of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka 565-0871, Japan.
Yamamoto
Yumiko
Y
Yamatodani
Atsushi
A
D000818:Animals; D002352:Carrier Proteins / Q000494:pharmacology* / Q000502:physiology; D006636:Histamine Release / Q000187:drug effects* / Q000502:physiology; D007032:Hypothalamus, Anterior / Q000187:drug effects* / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology* / Q000502:physiology; D000068797:Orexins; D051381:Rats; D017208:Rats, Wistar; D015854:Up-Regulation / Q000187:drug effects
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins