Decreased intercellular coupling after prolonged rapid stimulation in rabbit atrial muscle

J. Bredikis, F. Bukauskas, R. Veteikis

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21 Scopus citations

Abstract

Driving rabbit atrial trabeculae at a rapid rate for 15 minutes resulted in a decrease in the space constant for electrotonic decay from an average of 670 to 400 μm. Input resistance, R, as measured by use of a double-barrelled microelectrode, increased from a mean value of 380 kOhms to one of 600 kOhms. The time to return to control values after the end of rapid driving was 20-60 minutes. Similar effects of rapid driving were observed in the presence of atropine, propranolol, and atropine plus propranolol and phentolamine. According to the theory of current spread in a three-dimensional syncytium, a rise of input resistance should be interpreted mainly as an increase of cell-to-cell resistance. We advance the hypothesis that, when driven at their maximal possible rate (or when fibrillating), cardiac cells gain Na+ and Ca2+, and that this results in partial but reversible uncoupling.

Original languageEnglish (US)
Pages (from-to)815-820
Number of pages6
JournalCirculation research
Volume49
Issue number3
DOIs
StatePublished - 1981
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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