Back to Search
Start Over
Temperature-dependent postextrasystolic potentiation and Ca2+ recirculation fraction in canine hearts
- Source :
- American Journal of Physiology-Heart and Circulatory Physiology. 282:H403-H413
- Publication Year :
- 2002
- Publisher :
- American Physiological Society, 2002.
-
Abstract
- We have found that cardiac temperature proportionally changes O2 cost of contractility, defined as O2 consumption for myocardial total Ca2+handling normalized to contractility in terms of the end-systolic pressure-volume ratio (maximal elastance, E max), in the canine left ventricle (temperature sensitivity, Q10 = 2). We have separately found that a decrease in the recirculation fraction (RF) of Ca2+ within myocardial cells underlies an increased O2 cost of E max in stunned hearts. We therefore hypothesized that a similar change in RF would underlie the Q10 of O2 cost of E max. We tested this hypothesis by analyzing RF calculated from an exponential decay component of the transiently alternating postextrasystolic potentiation in the canine left ventricle. RF decreased from 0.7 to 0.5 as cardiac temperature increased from 33 to 38°C with Q10 of 0.5, reciprocal to that of O2 cost of E max. We conclude that Q10 of ATP-consuming reactions involved in Ca2+handling and E max response to it could reasonably account for the reciprocal Q10 of RF and O2 cost of E max.
- Subjects :
- medicine.medical_specialty
Physiology
chemistry.chemical_element
Fraction (chemistry)
Calcium
Ventricular Function, Left
Body Temperature
Contractility
Adenosine Triphosphate
Dogs
Heart Conduction System
Heart Rate
Physiology (medical)
Internal medicine
Heart rate
medicine
Carnivora
Animals
Computer Simulation
biology
Chemistry
Fissipedia
Models, Cardiovascular
biology.organism_classification
Myocardial Contraction
Ventricular Premature Complexes
Oxygen
Sarcoplasmic Reticulum
Endocrinology
Circulatory system
Cardiology
Electrical conduction system of the heart
Cardiology and Cardiovascular Medicine
Subjects
Details
- ISSN :
- 15221539 and 03636135
- Volume :
- 282
- Database :
- OpenAIRE
- Journal :
- American Journal of Physiology-Heart and Circulatory Physiology
- Accession number :
- edsair.doi.dedup.....de49acb940a611fc87a88aa1cb0d8295