Oxygen Costs of Left Ventricular Contractility for Dobutamine and Ca2+ in Normal Rat Hearts and the Cost for Dobutamine in Ca2+ Overload-Induced Failing Hearts
| Autor: | Susumu Sakata, Yoshiro Yoshikawa, Nobuoki Tabayashi, Hiromi Misawa, Miyako Takaki, Takehisa Abe, Shigeki Taniguchi, Kobayashi S, Chikako Takenaka |
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| Rok vydání: | 2002 |
| Předmět: |
Male
medicine.medical_specialty Cardiotonic Agents Physiology chemistry.chemical_element Calcium Oxygen Ventricular Function Left Elastance Contractility Calcium Chloride Oxygen Consumption Dobutamine Internal medicine medicine Animals Rats Wistar Ca2 overload Heart Failure Myocardial Stunning Myocardium Mean value General Medicine Left ventricular contractility Myocardial Contraction Rats chemistry Cardiology medicine.drug |
| Zdroj: | The Japanese Journal of Physiology. 52:163-171 |
| ISSN: | 0021-521X |
| DOI: | 10.2170/jjphysiol.52.163 |
| Popis: | The aim of the present study was to compare the oxygen (O(2)) cost of left ventricular (LV) contractility (equivalent maximal elastance; eEmax, an index for contractility) for dobutamine (a beta-receptor stimulant) with that for calcium (Ca(2+)) in normal rat hearts and to assess the O(2) cost of LV eEmax for dobutamine in Ca(2+) overload-induced failing rat hearts. The mean O(2) cost of LV eEmax (x10(-4) microl O(2) x beat(-1) x mmHg(-1) x ml x g(-2)) for Ca(2+) was 1.30+/-0.37 in 12 normal hearts, and for dobutamine it was 1.26+/-0.30 in eight different normal hearts. In the same five normal hearts, the mean O(2) cost of LV eEmax for dobutamine was 1.15+/-0.27, and for Ca(2+) it was 0.81+/-0.36. These mean values showed no significant differences between Ca(2+) and dobutamine. In five Ca(2+) overload-induced failing hearts, the mean O(2) cost of LV eEmax for Ca(2+) could not be assessed, but the mean O(2) cost of LV eEmax for dobutamine was 1.04+/-0.40. This mean value for dobutamine did not differ significantly from those (see above 1.26+/-0.30 or 1.15+/-0.27) in the normal hearts. The present results indicate, in terms of the coupling of mechanical work and energetics of the heart, that the total Ca(2+) handling VO(2) in excitation-contraction coupling against unit LV contractility change for dobutamine in the contractile failing hearts does not differ from that in the normal hearts. This suggests that in the Ca(2+) overload-induced contractile failing hearts, there were no changes in the sensitivity of the contractile machinery for Ca(2+), in the Ca(2+)/ATP in the total Ca(2+) handling, and in the ATP/VO(2) in the mitochondria. |
| Databáze: | OpenAIRE |
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