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1998 Fiscal Year Final Research Report Summary

Mechanoenergetics in mechanically unloaded myocardial slices

Research Project

Project/Area Number 09670053
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field General physiology
Research InstitutionNara Medical University

Principal Investigator

TAKAKI Miyako  Nara Medical University-Medicine professor, 医学部, 教授 (00033358)

Project Period (FY) 1997 – 1998
Keywordsmechanoenergetic / slices / 2, 3-butanedione monoxime / thapsigargin / cyclopiazonic acid / Ca^<2+>handling / basal metabolism / sarcoplasmic reticulum (SR) Ca^<2+>pump
Research Abstract

Increasing the population of elders, increasing acute and chronic cardiovascular diseases. Thus, physiological and pathophysiological aspects of failing hearts are important issue on Scientific Research on Priority Area. However, it is little known about the energetic efficiency of Ca^<2+> handling in normal and failing hearts on the beat to beat basis. Mechanoenergetics in whole hearts revealed an 0_2 wasting effect or Ca^<2+> futile cycling during the development of failing hearts. To this end, we have recently established a new measurement system of myocardial 0_2 consumption (V0_2) per min of mechanically unloaded rat left ventricular (LV)slices. Using this system, we have revealed that an increment in V0_2(delta V0_2) by electrical stiumulation represents energy expenditure for 0a2+ handling in the excitaiton-contraction (E-C) coupling. We consider that delta V0_2 does not contain V0_2 for residual cross-bridge cycling from the results showing no effect of 2,3-butanedione monoxime (BDM) on delta V0_2. We also established a measurement system slice mechanically unloaded contraction. This contraction is expressed by the motility index. BDM largely decreased this motility index. This result also supported no V0_2 for residual crossbridge cycling was included in delta V0_2. We also revealed that V0_2 without stimulation represents basal metabolism which is much higher than in other mammalian hearts and corresponds to that in the KCI-arrested rat whole heart prepartion. We finally obtained the results showing that sarcoplasmic reticulum (SR) Ga^<2+> pump blockers, thapsigargin and cyclopiazonic acid, did not reduce basal metabolic V0_2 but both of them reduced delta V0_2by 33 and 68% and reduced the motility index by 63 and 81%. We conclude that unloaded myocardial V0_2 is composed of V0_2 for E-C coupling and basal metabolism and does not contain V0_2 for residual crossbridge cycling.

  • Research Products

    (26 results)

All Other

All Publications (26 results)

  • [Publications] Shingo Yasuhara 他4名: "Myocardial VO_2 of mechanically unloaded contraction of rat ventricular slices measured by a new approach" American Journal Physiology(Heart Circ.Physiol.). 270・39. H1063-H1070 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Miyako Takaki 他5名: "Sarcoplasmic reticulum Ca^<2+> pump blockade decreases O_2 use of unloaded contracting rat heart slices : thapsigargin and cyclopiazonic acid" Journal of Molecular and Cellular Cardiology. 30. 649-659 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Miyako Takaki 他4名: "Mechanoenergetics of rat left ventricules in in situ and excised blood-perfused hearts and in unloaded rat left ventricular slices" Heart and Vessels. Suppl.12. 100-102 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Juichiro Shimizu 他10名: "A new integrative method to quantify total Ca^<2+> handling and futile Ca^<2+> cycling in failing hearts" American Journal Physiology(Heart Circ.Physiol. ). 275・44. H2325-H2333 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Takeshi Mikane 他9名: "Mechanism of constant contractile efficiency under cooling inotropy of myocardium : simulation" American Journal Physiology(Heart Circ.Physiol. ). 273・42. H2891-H2898 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yoshiki Hata 他9名: "Effects of thapsigargin and KCI on the O_2 use of the excised blood-perfused rat heart" Journal of Molecular and Cellular Cardiology. 30. 2137-2143 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Miyako Takaki 他8名: "Oxygen consumption and motility of mechanically unloaded myocardial slices" Mechanisms of work production and work absorption in muscle in Advances in Experimental Medicine and Biology. 453. 499-506 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Junichi Araki 他8名: "Ventricular pressure-volume area accounts for cardiac energy consumption of work production and absorption" Mechanisms of work production and work absorption in muscle in Advances in Experimental Medicine and Biology. 453. 491-498 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yoshiki Hata 他9名: "Ryanodine decreases internal Ca^<2+> recirculation fraction of the canine heart as studied by postextrasystolic transient alternans" Japanese Journal of Physiology. 47. 521-530 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yi Syuu 他9名: "Effects of Ca^<2+> and epinephrine on Ca^<2+> recireculation fraction and total ca^<2+> handing in canine left ventricles" Japanese Journal of Physiology. 48. 123-132 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Wakako Fujii 他5名: "Effects of intracoronary caffeine on left ventricular mechanoenergetics in Ca^<2+> overload failing rat hearts" Japanese Journal of Physiology. 48. 373-381 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yoshiki Hata 他9名: "Linear O_2 use-pressure-volume area relation from curved end-systolic pressure-volume relation of the blood-perfused rat left ventricle" Japanese Journal of Physiology. 48. 197-204 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Shinyu Lee 他7名: "Effects of myosin isozyme shift on curvilinearity of the left ventricular end-systolic pressure-volume relation of in situ rat hearts" Japanese Journal of Physiology. 48. 445-455 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Shingo Yasuhara: "Myocardial VO_2 of mechanically unloaded contraction of rat ventricular slices measured by a new approach" American Journal Physiology(Heart Circ.Physiol.). 270・39. H1063-H1070 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Miyako Takaki: "Sarcoplasmic reticulum Ca^<2+> pump blockade decreases O_2 use of unloaded contracting rat heart slices : thapsigargin and cyclopiazonic acid" Journal of Molecular and Cellular Cardiology. 30. 649-659 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Miyako Takaki: "Mechanoenergetics of rat left ventricules in in situ and excised blood-perfused hearts and in unloaded rat left ventricular slices" Heart and Vessels. Suppl.12. 100-102 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Juichiro Shimizu: "A new integrative method to quantify total Ca^<2+> handling and futile Ca^<2+> cycling in failing hearts" American Journal Physiology(Heart Circ.Physiol.). 275・44. H2325-H2333 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takeshi Mikane: "Mechanism of constant contractile efficiency under cooling inotropy of myocardium : simulation" American Journal Physiology(Heart Circ.Physiol.). 273・42. H2891-H2898 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yoshiki Hata: "Effects of thapsigargin and KCl on the O_2 use of the excised blood-perfused rat heart" Journal of Molecular and Cellular Cardiology. 30. 2137-2143 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Miyako Takaki: "Oxygen consumption and motility of mechanically unloaded myocardial slices" Mechanisms of work production and work absorption in muscle in Advances in Experimental Medicine and Biology. 453. 499-506 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Junichi Araki: "Ventricular pressure-volume area accounts for cardiac energy consumption of work production and absorption" Mechanisms of work production and work absorption in muscle in Advances in Experimental Medicine and Biology. 453. 491-498 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yoshiki Hata: "Ryanodine decreases internal Ca^<2+> recirculation fraction of the canine heart as studied by postextrasystolic transient alternans" Japanese Journal of Physiology. 47. 521-530 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yi Syuu: "Effects of Ca^<2+> and epinephrine on Ca^<2+> recirculation fraction and total Ca^<2+> handling in canine left ventricles" Japanese Journal of Physiology. 48. 123-132 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Wakako Fujii: "Effects of intracoronary caffeine on left ventricular mechanoenergetics in Ca^<2+> overload failing rat hearts" Japanese Journal of Physiology. 48. 373-381 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yoshiki Hata: "Linear O_2 use-pressure-volume area relation from curved end-systolic pressure-volume relation of the blood-perfused rat left ventricle" Japanese Journal of Physiology. 48. 197-204 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Shinyu Lee: "Effects of myosin isozyme shift on curvilinearity of the left ventricular end-systolic pressure-volume relation of in situ rat hearts" Japanese Journal of Physiology. 48. 445-455 (1998)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-12-08  

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