Document Detail


Influence of a period of inactivity on the duration of post-rest action potentials of the mammalian working ventricular myocardium in correlation to the preceding stimulation frequency.
MedLine Citation:
PMID:  2962206     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Experiments were carried out on the working right ventricular myocardium of adult cats, guinea-pigs and rabbits. Membrane voltage was recorded by the glass microelectrode technique and the preparations were stimulated with frequencies of 5, 1 and 0.2 Hz. After a steady state had been reached, a pause (TP) lasting 10-600 s was interpolated. The influence of TP on the duration (D) of post-rest action potentials (AP) was studied; the effect of the pause was measured at electric zero level (D0) and at further repolarization levels (-20, -40 and -60 mV, given here as D-20, D-40 and D-60). At 1 and 0.2 Hz frequency, the cat myocardium displayed lengthening of the AP proportional to the duration of the pause; at 5 Hz frequency, D0 reacted by lengthening up to TP = 120 s and to further pauses by slight shortening. D-60, at all frequencies, lengthened throughout the whole of the given TP range. The rabbit myocardium, at all the given frequencies, reacted up to TP = 60-120 s by marked shortening of post-rest AP at all repolarization levels; with longer pauses the AP lengthened. At 5 Hz frequency the guinea-pig myocardium reacted similarly to the cat myocardium; at the lower stimulation frequencies, the pause-induced changes in the post-rest AP were less strongly expressed. In all the given types of myocardium, the most pronounced post-rest AP reactions were those at electric zero level (the plateau phase of the AP); towards more negative repolarization values and with lower pre-pause stimulation frequencies they were less strongly expressed.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
P Pucelík; P Králícek; M Holická; M Lässigová; P Fiala
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Physiologia Bohemoslovaca     Volume:  36     ISSN:  0369-9463     ISO Abbreviation:  Physiol Bohemoslov     Publication Date:  1987  
Date Detail:
Created Date:  1988-01-25     Completed Date:  1988-01-25     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0175317     Medline TA:  Physiol Bohemoslov     Country:  CZECHOSLOVAKIA    
Other Details:
Languages:  eng     Pagination:  394-402     Citation Subset:  IM    
Affiliation:
Department of Physiology, Faculty of Medicine, Charles University, Plzen.
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MeSH Terms
Descriptor/Qualifier:
Action Potentials
Animals
Cats
Electric Stimulation
Female
Guinea Pigs
Heart / physiology*
Male
Rabbits
Species Specificity
Time Factors
Ventricular Function

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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