Force velocity relations of single cardiac muscle cells: calcium dependency.
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چکیده
منابع مشابه
Force velocity relations of single cardiac muscle cells: calcium dependency
Cellular cardiac preparations in which spontaneous activity was suppressed by EGTA buffering were isolated by microdissection. Uniform and reproducible contractions were induced by iontophoretically released calcium ions. No effects of a diffusional barrier to calcium ions between the micropipette and the contractile system were detected since the sensitivity of the mechanical performance for c...
متن کاملForce-velocity relations in mammalian heart muscle.
SONNENBLICK, EDMUND H. Force-velocity relations in mammalian heart muscle. Am. J. Physiol. 202 (5) : 931-939. 1962.Force-velocity relations were studied in the cat papillary muscle. As with skeletal muscle, a characteristic relation has been demonstrated between the velocity of shortening (V) and the force developed (PO). Two generalities have been shown to pertain. First, increasing initial mu...
متن کاملEffect of calcium on force-velocity-length relations of heart muscle of the cat.
The influence of calcium concentration in the bathing solution on the force-velocity relations of the isolated, electrically excited cat papillary muscle was examined. Shortening velocity was directly measured at minimum loads by unloading or load clamping the muscle from the preload (at the length, Lmax, where maximum active tension was developed) to 0 (zero-load clamp), 2, 5, 10, and 15% of t...
متن کاملThe force-velocity relation and stepwise shortening in cardiac muscle.
A series of experiments was carried out to determine the effects of load variation on the character of stepwise shortening. We imposed afterloaded isotonic contractions on rat ventricular trabeculae, and measured the effect of load on pause duration, i.e., on the duration of the periods during which there was no sarcomere shortening. Sarcomere lengths were measured by optical diffraction. Incre...
متن کاملModeling short-term interval-force relations in cardiac muscle.
This study employs two modeling approaches to investigate short-term interval-force relations. The first approach is to develop a low-order, discrete-time model of excitation-contraction coupling to determine which parameter combinations produce the degree of postextrasystolic potentiation seen experimentally. Potentiation is found to increase 1) for low recirculation fraction, 2) for high rele...
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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1977
ISSN: 0022-1295,1540-7748
DOI: 10.1085/jgp.69.2.221