Acetylcholine-sensitive potassium channels in human atrial myocytes

R. Sato, I. Hisatome, J. A. Wasserstrom, C. E. Arentzen, D. H. Singer*

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Single channel recording techniques were used to study acetylcholine (ACh)-sensitive K+ channel activity in human atrial myocytes isolated from specimens obtained during corrective cardiac surgery. Under conditions of cell-attached patch, the presence of ACh in the patch pipette activated K+ channels. Single channel activity occurred in periodic bursts. The channels exhibited a slope conductance of 46 ± 2 pS inwardly (means ± SD, n = 4). During a burst, both open and closed time histograms were fitted by a single exponential curve,suggesting the existence of one open and one closed state during a burst. Open probability increased directly with ACh concentration without affecting open time. The channel could be activated by GTP and guanosine 5'-O- (3-thiotriphosphate) (GTPγS) (in the presence and absence of ACh in the pipette, respectively). Slope conductance, the response to GTP and GTPγS, and the independence of activation from Ca2+ were similar to those for other species. In contrast, sensitivity to ACh appeared diminished compared with frog atrial myocytes.

Original languageEnglish (US)
Pages (from-to)H1730-H1735
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume259
Issue number6 28-6
DOIs
StatePublished - 1990

Keywords

  • G proteins
  • patch clamp
  • single channel measurements

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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