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The electrical activity of canine cardiac Purkinje fibers in sodium-free, calcium-rich solutions.
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MedLine Citation:
PMID:  4708407     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Propagated action potentials can be obtained in canine cardiac Purkinje fibers exposed to Na-free solutions containing no inorganic cation other than Ca and K. Essentially similar action potentials are obtained if Na is replaced by tetraethylammonium (TEA), tetramethylammonium (TMA), or choline. In a solution containing 128 mM TEA and 16.2 mM Ca the characteristics of these electrical responses were: maximum diastolic potential, -59 +/- 3.3 mV; overshoot, 20 +/- 6.8 mV; maximum upstroke velocity, 3.7 +/- 2.3 V/s; conduction velocity, 0.1 m/s; and action potential duration, 360 +/- 45 ms. The magnitude of the overshoot varied with log Ca(o) with a slope of about 30 mV/10-fold concentration change. The upstroke velocity was an approximately linear function of Ca(o). The active response was greatly diminished or abolished by Mn and D-600 but was unaffected by tetrodotoxin. These Ca-dependent responses appeared in a region of transmembrane potential (about -50 mV) at which the rapid Na-dependent upstroke is abolished even when Na is present.
Authors:
R S Aronson; P F Cranefield
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  The Journal of general physiology     Volume:  61     ISSN:  0022-1295     ISO Abbreviation:  J. Gen. Physiol.     Publication Date:  1973 Jun 
Date Detail:
Created Date:  1973-08-03     Completed Date:  1973-08-03     Revised Date:  2010-06-22    
Medline Journal Info:
Nlm Unique ID:  2985110R     Medline TA:  J Gen Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  786-808     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / drug effects*
Animals
Calcium / pharmacology*
Choline / pharmacology
Dogs
Electric Stimulation
Heart Conduction System / physiology*
Magnesium / pharmacology
Membrane Potentials
Quaternary Ammonium Compounds / pharmacology
Sodium*
Tetraethylammonium Compounds / pharmacology
Tetrodotoxin / pharmacology
Chemical
Reg. No./Substance:
0/Quaternary Ammonium Compounds; 0/Tetraethylammonium Compounds; 4368-28-9/Tetrodotoxin; 62-49-7/Choline; 7439-95-4/Magnesium; 7440-23-5/Sodium; 7440-70-2/Calcium
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Full Text
Journal Information
Journal ID (nlm-ta): J Gen Physiol
ISSN: 0022-1295
ISSN: 1540-7748
Publisher: The Rockefeller University Press
Article Information
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Copyright © 1973 by The Rockefeller University Press
Received Day: 25 Month: 1 Year: 1973
Print publication date: Day: 1 Month: 6 Year: 1973
Volume: 61 Issue: 6
First Page: 786 Last Page: 808
ID: 2203491
PubMed Id: 4708407

The Electrical Activity of Canine Cardiac Purkinje Fibers in Sodium-Free, Calcium-Rich Solutions
Ronald S. Aronson
Paul F. Cranefield
From The Rockefeller University, New York 10021


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