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: 292/6/G1474    most recent 00562.2006v1 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 ISI 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 ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Wan, S. Articles by Travagli, R. A. Search for Related Content PubMed PubMed Citation Articles by Wan, S. Articles by Travagli, R. A.

NEUROREGULATION AND MOTILITY

Glucagon-like peptide-1 excites pancreas-projecting preganglionic vagal motoneurons

¹Department of Neuroscience, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana; and ²Department of Physiology, Wuhan University School of Basic Medical Science, Wuhan, People's Republic of China

Submitted 11 December 2006 ; accepted in final form 12 February 2007

Glucagon-like peptide-1 (GLP-1) increases pancreatic insulin secretion via a direct action on pancreatic -cells. A high density of GLP-1-containing neurons and receptors is also present in brain stem vagal circuits; therefore, the aims of the present study were to investigate 1) whether identified pancreas-projecting neurons of the dorsal motor nucleus of the vagus (DMV) respond to exogenously applied GLP-1, 2) the mechanism(s) of action of GLP-1, and 3) whether the GLP-1-responsive neurons (putative modulators of endocrine secretion) could be distinguished from DMV neurons responsive to peptides that modulate pancreatic exocrine secretion, specifically pancreatic polypeptide (PP). Whole cell recordings were made from identified pancreas-projecting DMV neurons. Perfusion with GLP-1 induced a concentration-dependent depolarization in 50% of pancreas-projecting DMV neurons. The GLP-1 effects were mimicked by exendin-4 and antagonized by exendin-(9–39). In 60% of the responsive neurons, the GLP-1-induced depolarization was reduced by tetrodotoxin (1 µM), suggesting both pre- and postsynaptic sites of action. Indeed, the GLP-1 effects were mediated by actions on potassium currents, GABA-induced currents, or both. Importantly, neurons excited by GLP-1 were unresponsive to PP and vice versa. These data indicate that 1) GLP-1 may act on DMV neurons to control pancreatic endocrine secretion, 2) the effects of GLP-1 on pancreas-projecting DMV neurons are mediated both via a direct excitation of their membrane as well as via an effect on local circuits, and 3) the GLP-1-responsive neurons (i.e., putative endocrine secretion-controlling neurons) could be distinguished from neurons responsive to PP (i.e., putative exocrine secretion-controlling neurons).

brain stem; electrophysiology; vagus; pancreas

This article has been cited by other articles:

				S. Wan, K. N. Browning, F. H. Coleman, G. Sutton, H. Zheng, A. Butler, H.-R. Berthoud, and R. A. Travagli Presynaptic Melanocortin-4 Receptors on Vagal Afferent Fibers Modulate the Excitability of Rat Nucleus Tractus Solitarius Neurons J. Neurosci., May 7, 2008; 28(19): 4957 - 4966. [Abstract] [Full Text] [PDF]

				S. Wan, F. H. Coleman, and R. A. Travagli Cholecystokinin-8s excites identified rat pancreatic-projecting vagal motoneurons Am J Physiol Gastrointest Liver Physiol, August 1, 2007; 293(2): G484 - G492. [Abstract] [Full Text] [PDF]