HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 285/6/G1091    most recent 00193.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (11) Citing Articles via Google Scholar Google Scholar Articles by Flemström, G. Articles by Åkerman, K. E. O. Search for Related Content PubMed PubMed Citation Articles by Flemström, G. Articles by Åkerman, K. E. O.

HORMONES AND SIGNALING

Short fasting dramatically decreases rat duodenal secretory responsiveness to orexin A but not to VIP or melatonin

Division of Physiology, Department of Neuroscience, Uppsala University, SE-751 23 Uppsala, Sweden

Submitted 28 April 2003 ; accepted in final form 15 July 2003

Orexins are involved in the central nervous control of appetite and behavior, and in addition, they are present in endocrine cells and/or neurons in the intestine. The role of these peptides in peripheral regulation of intestinal secretion has not been investigated. We thus compared the effects of orexin A and some established secretagogues on duodenal HCO₃^- secretion in fed rats with effects in rats exposed to short (overnight) food deprivation. Rats were anesthetized with thiobarbiturate, a 12-mm segment of proximal duodenum with intact blood supply was cannulated in situ, and the alkaline secretion was titrated by pH stat. Secretagogues were supplied specifically to the duodenum by close intra-arterial infusion. Orexin A (60-600 pmol·kg^-1·h^-1) caused marked and dose-dependent stimulation of the duodenal secretion in fed animals but did not affect secretion in overnight food-deprived animals. Similarly, short fasting caused a 100-fold increase in the amount of the muscarinic agonist bethanechol (from 50 to 5,000 nmol·kg^-1·h^-1) required for stimulation of the secretion. In contrast, the secretory responses to VIP (50-1,000 pmol·kg^-1·h^-1) and melatonin (20-200 nmol·kg^-1·h^-1) were not affected. The appetite-regulating peptide orexin A is thus a stimulant of intestinal secretion, but the response to this peptide as well as the muscarinic agonist bethanechol is markedly dependent on previous intake of food. Overnight fasting is a standard experimental procedure in studies of gastrointestinal function and pathophysiology in humans and animals. Studies made on neuroendocrine control of intestinal secretion may require reevaluation with respect to feeding status.

bethanochol; bicarbonate secretion; duodenal mucosal protection; food deprivation; vasoactive intestinal polypeptide

This article has been cited by other articles:

				M. W. Bengtsson, K. Makela, K.-H. Herzig, and G. Flemstrom Short food deprivation inhibits orexin receptor 1 expression and orexin-A induced intracellular calcium signaling in acutely isolated duodenal enterocytes Am J Physiol Gastrointest Liver Physiol, March 1, 2009; 296(3): G651 - G658. [Abstract] [Full Text] [PDF]

				M. W. Bengtsson, K. Makela, M. Sjoblom, S. Uotila, K. E. O. Akerman, K.-H. Herzig, and G. Flemstrom Food-induced expression of orexin receptors in rat duodenal mucosa regulates the bicarbonate secretory response to orexin-A Am J Physiol Gastrointest Liver Physiol, August 1, 2007; 293(2): G501 - G509. [Abstract] [Full Text] [PDF]

				G. Flemstrom and M. Sjoblom Epithelial Cells and Their Neighbors. II. New perspectives on efferent signaling between brain, neuroendocrine cells, and gut epithelial cells Am J Physiol Gastrointest Liver Physiol, September 1, 2005; 289(3): G377 - G380. [Abstract] [Full Text] [PDF]

				A. Allen and G. Flemstrom Gastroduodenal mucus bicarbonate barrier: protection against acid and pepsin Am J Physiol Cell Physiol, January 1, 2005; 288(1): C1 - C19. [Abstract] [Full Text] [PDF]