Document Detail

On-line calorimetry in the arterially perfused rabbit interventricular septum.
MedLine Citation:
PMID:  7114238     Owner:  NLM     Status:  MEDLINE    
A method has been developed to measure myocardial heat production simultaneously with mechanical (developed tension, rate of contraction and relaxation) and metabolic parameters in the arterially perfused interventricular septum of the rabbit. The system allows control of rest tension, frequency of contraction, temperature, and composition of the perfusate. The technique is based on the differential measurement of the heat flux from the muscle to the calorimetric bath. This technique is able to resolve changes in heat production as small as 0.06 mW. The resting heat production measured with the present calorimeter (1.62 +/- 0.1 mW/g wet tissue) agrees with that obtained with thermopiles and with that calculated from measurements of oxygen consumption. The heat per contraction (6.5 +/- 1.4 mJ/g wet tissue) also agreed with that measured with thermopiles in rabbit papillary muscles. The heat production measured at 22 degrees C under severe hypoxia can be fully explained by the addition of the expected change of enthalpy due to the reaction 0.5 glucose-lactate, calculated on the basis of the lactate measured in the perfusate, and the expected change of enthalpy of oxygen consumption [assuming that all remaining O2 in perfusate (0.09 vol%) is used for combustion of glucose]. These results clearly demonstrated the feasibility of this method for the correlation of changes in energy turnover, through the measurement of the heat production, with mechanical and metabolic processes on-line in arterially perfused septum.
J E Ponce-Hornos; N V Ricchiuti; G A Langer
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  243     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1982 Aug 
Date Detail:
Created Date:  1982-10-12     Completed Date:  1982-10-12     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H289-95     Citation Subset:  IM    
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MeSH Terms
Anoxia / physiopathology
Body Temperature Regulation
Calorimetry / methods*
Electric Stimulation
Evaluation Studies as Topic
Heart Septum / physiology*
Heart Ventricles
Muscle Contraction

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

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