Basic Medicine, Molecular and Cellular Biology

Clinical Physiology

To Investigate the Mechanism Underlying Sudden Cardiac Death Using Multicellular Cardiac Muscle

Health Sciences Course

  • Master / Doctoral Degree


MIURA, MasahitoMIURA, Masahito
MIURA, Masahito

Professor, M.D. Ph.D.

  • TEL


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    mmiura* (Please convert "*" into "@".)

*Concurrent Position

Research Theme

  • Elucidation of endotoxin effects on diaphragm muscle contractility using MyD88KO mice
  • Relationship between muscle contraction and arrhythmogenesis
  • Diaphragm muscle contractility in bronchial asthma model
Research Keywords:

diaphragm muscle contractility, endotoxin, MyD88KO mice, arrhythmias, intracellular calcium

Technical Keywords:

dissected diaphragm muscle, electrical stimulation, knockout mice, multicellular cardiac muscle preparation, fluorescent dye loading

Laboratory Introduction

This department teaches medical technology related to respiratory and cardiac physiology and basically investigates diaphragm and heart muscle contractility using animal models as follows: (1) The respiratory muscle is an organ to drive lung movements, and the decreased muscle contractility is closely related to a respiratory failure, therefore, to prevent respiratory failure is a very important research theme. To investigate respiratory failure in septic shock, we have measured force-frequency curves (Figure.1) as a diaphragm muscle contractility after endotoxin injection in normal mice and MyD88KO mice. (2) Almost 60,000 people suddenly die chiefly due to lethal arrhythmias in Japan, but we have no effective therapy except for ICD implantation. It is well known that in ventricular muscle, intracellular Ca2+ is deeply involved in the occurrence of such arrhythmias by enhancing delayed afterdepolarizations (Figure.2). In this department, we thus focus on intracellular Ca2+ dynamics during muscle contraction, investigating how lethal arrhythmias occur in diseased hearts using rat ventricular muscle.

Figure 1. Example of force-frequency curve measurement

Figure 1. Example of force-frequency curve measurement

Figure 2. Induction of arrhythmias due to disturbance of intracellular Ca2+

Figure 2. Induction of arrhythmias due to disturbance of intracellular Ca2+

Recent Publications

  • Daniels RE, et al. Cardiac expression of ryanodine receptor subtype 3; a strategic component of intracellular Ca2+ release system in Purkinje fibers of large mammalian heart. J Mol Cell Cardiol. 104: 31-42, 2017
  • Miura M, et al. Effect of myofilament Ca2+ sensitivity on Ca2+ wave propagation in rat ventricular muscle. J Mol Cell Cardiol. 84:162-169, 2015
  • Miura M, et al. Role of reactive oxygen species and Ca2+ dissociation from the myofilaments in determination of Ca2+ wave propagation in rat cardiac muscle. J Mol Cell Cardiol. 56:97-105, 2013
  • Miura M, et al. Regional increase in extracellular potassium can be arrhythmogenic due to nonuniform muscle contraction in rat ventricular muscle. Am J Physiol 302:H2301-H2309, 2012
  • Miura M, et al. Effect of non-uniform muscle contraction on sustainability and frequency of triggered arrhythmias in rat cardiac muscle. Circulation 121:2711-2717, 2010