Frequency-dependent myofilament Ca2+desensitization in failing rat myocardium
نویسندگان
چکیده
منابع مشابه
Myofilament calcium regulation in human myocardium.
BACKGROUND We investigated whether decreased myofilament calcium contractile activation may, in part, contribute to heart failure. METHODS AND RESULTS Calcium concentration required for 50% activation and Hill coefficient for fibers from nonfailing and failing human hearts at pH 7.1 were not different. Maximum calcium-activated force (F(max)) was also not different. However, at pH 6.8 and 6.9...
متن کاملFrequency-dependent acceleration of relaxation involves decreased myofilament calcium sensitivity.
The force-frequency relationship is an intrinsic modulator of cardiac contractility and relaxation. Force of contraction increases with frequency, while simultaneously a frequency-dependent acceleration of relaxation occurs. While frequency dependency of calcium handling and sarcoplasmic reticulum calcium load have been well described, it remains unknown whether frequency-dependent changes in m...
متن کاملMyofilament lattice spacing as a function of sarcomere length in isolated rat myocardium.
The Frank-Starling relationship of the heart has, as its molecular basis, an increase in the activation of myofibrils by calcium as the sarcomere length increases. It has been suggested that this phenomenon may be due to myofilaments moving closer together at longer lengths, thereby enhancing the probability of favorable acto-myosin interaction, resulting in increased calcium sensitivity. Accor...
متن کاملBeneficial effects of SR33805 in failing myocardium.
AIMS SR33805, a potent Ca(2+) channel blocker, increases cardiac myofilament Ca(2+) sensitivity in healthy rat cardiomyocytes. Therefore, the aim of the present study was to evaluate the effects of SR33805 on contractile properties in ischaemic failing hearts after myocardial infarction (MI) in vivo and in vitro at the cellular level. METHODS AND RESULTS The effect of SR33805 (10 µM) was test...
متن کاملImpact of osmotic compression on sarcomere structure and myofilament calcium sensitivity of isolated rat myocardium.
Changes in interfilament lattice spacing have been proposed as the mechanism underlying myofilament length-dependent activation. Much of the evidence to support this theory has come from experiments in which high-molecular-weight compounds, such as dextran, were used to osmotically shrink the myofilament lattice. However, whether interfilament spacing directly affects myofilament calcium sensit...
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ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 2007
ISSN: 0022-3751
DOI: 10.1113/jphysiol.2007.134486