Coupling of a P2Z-like purinoceptor to a fatty acid-activated K+ channel in toad gastric smooth muscle cells

H. Zou, M. Ugur, R.M. Drummond, J.J. Singer

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

1. Extracellular application of ATP generates two whole-cell currents in toad gastric smooth muscle cells: an immediate inward non-selective cation current (due to the activation of a P2X or P2Z-like receptor) and a slowly developing outward K+ current. The inward non-selective cation current depends on the continuous presence of ATP while the outward K+ current can last for minutes after ATP application ceases. 2. In cell-attached patches, application of ATP to the extra-patch membrane can activate K+ channels in the patch indicating that a diffusible cellular messenger may be involved. The characteristics of these K+ channels are similar to those of a previously described fatty acid-activated K+ channel that is also a stretch-activated channel. 3. This whole-cell K+ current can be induced by ATP in the absence of extracellular Ca2+ (with EGTA present to chelate trace amounts). However, the current generated in the presence of extracellular Ca2+ is considerably larger. 4. The pharmacological profiles for the activation of the non-selective cation current and the K+ current are similar, suggesting that the same P2Z-like receptor could be mediating both responses. This type of plasma membrane receptor/channel-channel coupling by a process that does not appear to involve Ca2+ flow through the receptor/channel or a subsequent membrane potential change may be representative of a new class of signalling mechanisms.
Original languageEnglish
Pages (from-to)59-70
Number of pages11
JournalJournal of Physiology
Volume534
Issue number1
DOIs
Publication statusPublished - 1 Jul 2001

Keywords

  • P(2Z) purinergic receptors
  • extracellular atp
  • phospholipase D
  • BAC1.2F5 macrophages
  • potassium channels
  • calcium
  • nucleotides
  • secretion
  • agonists

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