Purkinje-muscle coupling and endocardial response to hyperkalemia, hypoxia, and acidosis.

R. F. Gilmour, J. J. Evans, D. P. Zipes

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Previously we found that combined hyperkalemia, hypoxia, and acidosis depressed the electrical activity of canine epicardium more than that of endocardium or Purkinje fibers. In this study, we determined whether the resistance of endocardium to these components of ischemia was due to electrotonic interactions with Purkinje fibers. The effects of combined hyperkalemia, hypoxia, and acidosis were tested on endocardial cells that were electrically uncoupled from Purkinje cells ("uncoupled" endocardium), due to their location or to prior exposure to elevated [Ca2+]. During control, action potentials in uncoupled endocardium had shorter durations than endocardium coupled to Purkinje ("coupled" endocardium), but had similar amplitudes, upstroke velocities, and resting potentials. During combined hyperkalemia, hypoxia, and acidosis, action potentials in uncoupled endocardium were more depressed than in coupled endocardium and resembled those in depressed epicardium. In addition, the combination of these components of ischemia produced electrical uncoupling at the Purkinje-muscle junction, although each component alone did not. Thus the resistance of endocardial cells to some components of ischemia appears to involve electrotonic interactions with Purkinje cells, which may be prevented by ischemia-induced electrical uncoupling.

Original languageEnglish
JournalThe American journal of physiology
Volume247
Issue number2 Pt 2
StatePublished - Aug 1984
Externally publishedYes

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Endocardium
Hyperkalemia
Acidosis
Muscles
Ischemia
Purkinje Fibers
Purkinje Cells
Pericardium
Action Potentials
Hypoxia
Membrane Potentials
Canidae

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Purkinje-muscle coupling and endocardial response to hyperkalemia, hypoxia, and acidosis. / Gilmour, R. F.; Evans, J. J.; Zipes, D. P.

In: The American journal of physiology, Vol. 247, No. 2 Pt 2, 08.1984.

Research output: Contribution to journalArticle

Gilmour, R. F. ; Evans, J. J. ; Zipes, D. P. / Purkinje-muscle coupling and endocardial response to hyperkalemia, hypoxia, and acidosis. In: The American journal of physiology. 1984 ; Vol. 247, No. 2 Pt 2.
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