Calcium, cross-bridges, and the Frank-Starling relationship.
نویسندگان
چکیده
The steep relationship between active force and length in cardiac muscle is based on a length dependence of myofilament Ca(2+) sensitivity. However, it is not muscle length but the lateral spacing between actin and myosin filaments that sets the level of Ca(2+) sensitivity, mainly through modulation of myosin-mediated activation of the thin filament.
منابع مشابه
AHEART Mar. 45/3
Landesberg, Amir, and Samuel Sideman. Regulation of energy consumption in cardiac muscle: analysis of isometric contractions. Am. J. Physiol. 276 (Heart Circ. Physiol. 45): H998–H1011, 1999.—The well-known linear relationship between oxygen consumption and force-length area or the force-time integral is analyzed here for isometric contractions. The analysis, which is based on a biochemical mode...
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The well-known linear relationship between oxygen consumption and force-length area or the force-time integral is analyzed here for isometric contractions. The analysis, which is based on a biochemical model that couples calcium kinetics with cross-bridge cycling, indicates that the change in the number of force-generating cross bridges with the change in the sarcomere length depends on the for...
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The Frank-Starling relationship provides beat-to-beat regulation of ventricular function by matching ventricular input and output. This review addresses the subcellular mechanisms by which the ventricle adjusts its output (i.e. stroke volume) by changes in end-diastolic volume. The subcellular processes are placed in the context of the four phases of the cardiac cycle with emphasis on the sarco...
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We tested the hypothesis that the Frank-Starling relationship is mediated by changes in the rate of cross-bridge detachment in cardiac muscle. We simultaneously measured isometric force development and the rate of ATP consumption at various levels of Ca2+ activation in skinned rat cardiac trabecular muscles at three sarcomere lengths (2.0, 2.1, and 2.2 μm). The maximum rate of ATP consumption w...
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Previous work suggests that titin-based passive tension is a factor in the Frank-Starling mechanism of the heart, by increasing length-dependent activation (LDA) through an increase in calcium sensitivity at long sarcomere length. We tested this hypothesis in a mouse model (N2B KO model) in which titin-based passive tension is elevated as a result of the excision of the N2B element, one of card...
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عنوان ژورنال:
- News in physiological sciences : an international journal of physiology produced jointly by the International Union of Physiological Sciences and the American Physiological Society
دوره 16 شماره
صفحات -
تاریخ انتشار 2001