ATP is a mediator of the fast inhibitory junction potential in human jejunal circular smooth muscle

L. Xue, G. Farrugia, M. G. Sarr, J. H. Szurszewski

Research output: Contribution to journalArticle

68 Scopus citations

Abstract

The neurotransmitter(s) that generates the fast component of the inhibitory junction potential (IJP-F) in human jejunal circular smooth muscle is not known. The aim of this study was to determine the role of ATP and purinergic receptors in the generation of the IJP-F in human jejunal circular smooth muscle strips. The P2-receptor antagonist suramin (100 μM) reduced the IJP-F by 28%. Apamin (1 μM) reduced the IJP-F by 25%. Desensitization of muscle strips with the putative P(2x)-receptor agonist α,β-methylene ATP (α,β-MeATP, 100 μM) decreased the IJP-F by 44%, and desensitization with the putative P(2y)-receptor agonist adenosine 5'-O-2-thiodiphosphate (ADPβS) completely abolished the IJP-F. Desensitization with the putative P(2y)- receptor agonist 2-methylthioATP had no effect on the IJP-F. Exogenous ATP evoked a hyperpolarization with a time course that matched the IJP-F. The ATP-evoked hyperpolarization was reduced by apamin and suramin, reduced by desensitization with α,β-MeATP (69% decrease), and abolished by desensitization with ADPβS. These data suggest that the IJP-F in human jejunal circular smooth muscle is mediated in part by ATP through an ADPβS- sensitive P2 receptor.

Original languageEnglish (US)
Pages (from-to)G1373-G1379
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume276
Issue number6 39-6
StatePublished - Jun 1999

Keywords

  • Microelectrodes
  • Neurotransmission
  • Purinergic receptors

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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