Effect of ventricular stretch on contractile strength, calcium transient, and cAMP in intact canine hearts

Koji Todaka, Kazuhide Ogino, Anguo Gu, Daniel Burkhoff

研究成果: ジャーナルへの寄稿記事

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Isovolumic contractions were imposed by intraventricular balloon in 39 isolated, blood-perfused canine hearts to investigate the effects of myocardial stretch on contractile force. After stabilization at 37°C, left ventricular volume was increased so that end-diastolic pressure increased from 0 to 5 mmHg. After the immediate increase in developed pressure [DP; from 37 ± 14 to 82 ± 22 mmHg (means ± SD)], there was a slow secondary rise in DP (97 ± 27 mmHg) that peaked at 3 min. However, DP subsequently decreased over the next 7 min back to the initial value (84 ± 25 mmHg). Light emission from macroinjected aequorin (n = 10 hearts) showed that changes in intracellular calcium [3 min: 124 ± 15% (P < 0.01); 10 min: 99 ± 18% of baseline] paralleled DP changes. Increases in myocardial adenosine 3',5'-cyclic monophosphate (cAMP) content (n = 12) accompanied the secondary rise in DP. In contrast, the gradual elevation of DP after the stretch was not exerted during continuous [β-adrenergic stimulation by isoproterenol. Thus, in contrast to isolated muscle, stretch only transiently increases intracellular calcium and contractile strength in intact hearts. The findings of changes in cAMP and abolition of the phenomena by β-stimulation suggest that a primary stretch-mediated influence on cAMP metabolism may underlie these phenomena.

元の言語英語
ページ(範囲)H990-H1000
ジャーナルAmerican Journal of Physiology - Heart and Circulatory Physiology
274
発行部数3 43-3
出版物ステータス出版済み - 3 1 1998

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All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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