title: Central Orexin-A stimulates pancreatic exocrine secretion via the vagus.
abstract: BACKGROUND
  Digestive organs are controlled from the central nervous system, and the vagus nerve plays an important role. Orexins are recently purified neuropeptides localized in neurons within the lateral hypothalamus.
  
  
  OBJECTIVE
  To examine the effects of centrally injected Orexin-A and B on pancreatic exocrine secretion in conscious rats.
  
  
  METHODS
  Rats were prepared with cannulae draining bile and pancreatic juice separately. The experiments were conducted without anesthesia on day 4 or 5 after the operation.
  
  
  RESULTS
  Intracerebroventricular administration of Orexin-A (0.25, 0.5, and 1.0 nmol) significantly increased pancreatic fluid and protein output in a dose-dependent manner. A significant stimulatory effect of Orexin-B was not observed. Pretreatment with the ganglion blocker hexamethonium and with atropine completely abolished the stimulatory effect of central Orexin-A. Central Orexin-A significantly increased pancreatic secretion after pretreatment with omeprazole. Intravenous injection of Orexin-A had no effect. Centrally administered Orexin-A stimulated the vagal efferent nerve in anesthetized rats.
  
  
  CONCLUSIONS
  Centrally administered Orexin-A stimulates pancreatic exocrine secretion through the vagal efferent nerve, and the stimulatory action is independent of gastric acid secretion.
authors.affiliation: Department of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan. miyasaka@tmig.or.jp
authors.forename: Kyoko
authors.initials: K
authors.lastname: Miyasaka
authors.forename: Masao
authors.initials: M
authors.lastname: Masuda
authors.forename: Setsuko
authors.initials: S
authors.lastname: Kanai
authors.forename: Norikazu
authors.initials: N
authors.lastname: Sato
authors.forename: Mieko
authors.initials: M
authors.lastname: Kurosawa
authors.forename: Akihiro
authors.initials: A
authors.lastname: Funakoshi
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002352:Carrier Proteins / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005730:Ganglionic Blockers / Q000494:pharmacology; D018738:Hexamethonium / Q000494:pharmacology; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008297:Male; D009479:Neuropeptides / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009853:Omeprazole / Q000494:pharmacology; D000068797:Orexins; D010179:Pancreas / Q000294:innervation* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology*
chemical_list: D002352:Carrier Proteins; D005730:Ganglionic Blockers; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D018738:Hexamethonium; D001285:Atropine; D009853:Omeprazole