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Electrophysiology of an insect heart.
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MedLine Citation:
PMID:  13932039     Owner:  NLM     Status:  MEDLINE    
Bioelectric activity in single cells of the moth myocardium has been measured in situ with intracellular microelectrodes with particular reference to the bizarre ionic medium which bathes the tissues. Resting potentials averaged 47 mv, inside negative with respect to outside, despite a value of 11 mv calculated on the basis of transmembrane potassium concentration gradients. Action potentials overshoot as much as 12 mv in the virtual absence of extracellular sodium. Two "types" of action potentials have been recorded; one that resembles vertebrate atrial action potentials is found in the cephalic region of the tubular heart, and the other, similar in contour to vertebrate ventricular action potentials, is found in the areas posterior to the first abdominal segment. Histological sections indicate no structural differences between the two areas. Typical cardiac pacemaker type potentials occur but are not topographically localized. The effects of the omission from the perfusion fluid of the four major cationic constituents, Na(+), K(+), Ca(++) and Mg(++), on resting and action potentials may be summarized as: no effect, hyperpolarization, prolonged repolarization, and depolarization, respectively.
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of general physiology     Volume:  46     ISSN:  0022-1295     ISO Abbreviation:  J. Gen. Physiol.     Publication Date:  1963 Mar 
Date Detail:
Created Date:  1963-12-01     Completed Date:  1998-11-01     Revised Date:  2010-06-22    
Medline Journal Info:
Nlm Unique ID:  2985110R     Medline TA:  J Gen Physiol     Country:  Not Available    
Other Details:
Languages:  eng     Pagination:  803-21     Citation Subset:  OM    
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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 ©, 1963, by The Rockefeller Institute Press
Received Day: 9 Month: 7 Year: 1962
Print publication date: Day: 1 Month: 3 Year: 1963
Volume: 46 Issue: 4
First Page: 803 Last Page: 821
ID: 2195296
PubMed Id: 13932039

Electrophysiology of an Insect Heart
Frances V. McCann
From the Department of Physiology, Dartmouth Medical School, Hanover, New Hampshire

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