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/G1483    most recent 00450.2006v1 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 (5) Citing Articles via Google Scholar Google Scholar Articles by Wang, G.-D. Articles by Wood, J. D. Search for Related Content PubMed PubMed Citation Articles by Wang, G.-D. Articles by Wood, J. D.

NEUROREGULATION AND MOTILITY

Inhibitory neuromuscular transmission mediated by the P2Y₁ purinergic receptor in guinea pig small intestine

Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio

Submitted 29 September 2006 ; accepted in final form 8 February 2007

ATP is a putative inhibitory neurotransmitter responsible for inhibitory junction potentials (IJPs) at neuromuscular junctions (IJPs) in the intestine. This study tested the hypothesis that the purinergic P2Y₁ receptor subtype mediates the IJPs. IJPs were evoked by focal electrical stimulation in the myenteric plexus and recorded with "sharp" intracellular microelectrodes in the circular muscle coat. Stimulation evoked three categories of IJPs: 1) purely purinergic IJPs, 2) partially purinergic IJPs, and 3) nonpurinergic IJPs. Purely purinergic IJPs were suppressed by the selective P2Y₁ purinergic receptor antagonist MRS2179. Purely purinergic IJPs comprised 26% of the IJPs. Partially purinergic IJPs (72% of the IJPs) consisted of a component that was abolished by MRS2179 and a second unaffected component. The MRS2179-insensitive component was suppressed or abolished by inhibition of formation of nitric oxide by N-nitro-L-arginine methyl ester (L-NAME) in some, but not all, IJPs. An unidentified neurotransmitter, different from nitric oxide, mediated the second component in these cases. Nonpurinergic IJPs were a small third category (4%) of IJPs that were abolished by L-NAME and unaffected by MRS2179. Exogenous application of ATP evoked IJP-like hyperpolarizing responses, which were blocked by MRS2179. Application of apamin, which suppresses opening of small-conductance Ca²⁺-operated K⁺ channels in the muscle, decreased the amplitude of the purinergic IJPs and the amplitude of IJP-like responses to ATP. The results support ATP as a neurotransmitter for IJPs in the intestine and are consistent with the hypothesis that the P2Y₁ purinergic receptor subtype mediates the action of ATP.

adenosine 5'-triphosphate; neurotransmission; enteric nervous system; intestinal motility; smooth muscle

This article has been cited by other articles:

				D. Gallego, V. Gil, J. Aleu, M. Auli, P. Clave, and M. Jimenez Purinergic and nitrergic junction potential in the human colon Am J Physiol Gastrointest Liver Physiol, September 1, 2008; 295(3): G522 - G533. [Abstract] [Full Text] [PDF]

				B. McDonnell, R. Hamilton, M. Fong, S. M. Ward, and K. D. Keef Functional evidence for purinergic inhibitory neuromuscular transmission in the mouse internal anal sphincter Am J Physiol Gastrointest Liver Physiol, April 1, 2008; 294(4): G1041 - G1051. [Abstract] [Full Text] [PDF]

				B. F. King and A. Townsend-Nicholson Involvement of P2Y1 and P2Y11 Purinoceptors in Parasympathetic Inhibition of Colonic Smooth Muscle J. Pharmacol. Exp. Ther., March 1, 2008; 324(3): 1055 - 1063. [Abstract] [Full Text] [PDF]