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PMID: 4092068 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.

Gating of delayed rectification in acutely isolated canine cardiac Purkinje myocytes. Evidence for a single voltage-gated conductance.

Biophysical journal ·Vol. 48 ·No. 6 ·1985-12-00 ·Pages 1059-64

Gintant GA, Datyner NB, Cohen IS

Abstract

Studies of time-dependent, plateau outward current (delayed rectification) in the heart are complicated by the accumulation and depletion of K+ ions in intercellular clefts. To minimize this problem, we studied delayed rectification in acutely isolated (enzymic solution, gentle agitation) canine cardiac Purkinje myocytes using the single microelectrode voltage-clamp technique. We found a sigmoidal voltage-dependence for activation of outward plateau current, with maximal activation occurring at potentials near -10 mV. The activation and deactivation of plateau outward current was adequately described as the sum of a fast and slow exponential component. A comparison of the time course of activation of plateau outward current and the "envelope" of tail currents suggests that a single voltage-gated conductance with one open and two closed states can account for delayed rectification in Purkinje myocytes. These results differ from those previously obtained with intact sheep Purkinje fibers in which two time-dependent conductances were postulated to account for delayed rectification (Noble, D., and R. W. Tsien, 1969, J. Physiol. (Lond.), 200:205-231).

MeSH Terms
Action Potentials Animals Dogs Electric Conductivity Heart Conduction System/physiology In Vitro Techniques Kinetics Potassium/metabolism Purkinje Fibers/physiology
Chemicals
Potassium
Authors & Affiliations
3 authors, click to expand affiliations / ORCID
Gintant G A
Datyner N B
Cohen I S
References (21)
21 references, click to expand
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Article Info
Journal
Biophysical journal
Abbr.
Biophys J
ISSN
0006-3495
DOI
10.1016/S0006-3495(85)83869-8
Published
1985-12-00
Pages
1059-64
Language
English
Region
United States
NLM ID
0370626
PMCID
PMC1329439
Subset
IM
Grants
NHLBI NIH HHS · HL 20558 · United States
NHLBI NIH HHS · HL 28958 · United States
External Links
PubMed source DOI: 10.1016/S0006-3495(85)83869-8 PMC Full Text View journal details
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