منابع مشابه
Regulation of Cardiac Muscle Contractility
The heart's physiological performance, unlike that of skeletal muscle, is regulated primarily by variations in the contractile force developed by the individual myocardial fibers. In an attempt to identify the basis for the characteristic properties of myocardial contraction, the individual cardiac contractile proteins and their behavior in contractile models in vitro have been examined. The lo...
متن کاملMaximum Velocity as an Index of Contractility in Cardiac Muscle
The use of maximum velocity of shortening (Vmas) as an index of contractility has been based on the assumption that Vraox of muscle fibers is equivalent t° Vmax of the contractile element. It is shown here that such equivalence applies to the two-element model of skeletal muscle but not to three-element models of cardiac muscle. Analysis of published data in terms of the Voigt and Maxwell three...
متن کامل2-deoxy-ATP enhances contractility of rat cardiac muscle.
To investigate the kinetic parameters of the crossbridge cycle that regulate force and shortening in cardiac muscle, we compared the mechanical properties of cardiac trabeculae with either ATP or 2-deoxy-ATP (dATP) as the substrate for contraction. Comparisons were made in trabeculae from untreated rats (predominantly V1 myosin) and those treated with propylthiouracil (PTU; V3 myosin). Steady-s...
متن کاملImmobilized catecholamine and cocaine effects on contractility of cardiac muscle.
Isoproterenol, norepinephrine, and epinephrine covalently bound to glass beads exert a positive inotropic effect on isometrically contracting papillary muscles from cats. Immobilized isoproterenol maintains increases in force and velocity of contraction for more than 5 hr. 1 muM Cocaine potentiates the action of immobilized norepinephrine, isoproterenol, and epinephrine, but not of isoprotereno...
متن کاملRegulation of cardiac contractility: high time for FXYD.
FXYD PROTEINS COMPRISE a family of small integral membrane proteins that are regulators of ion transport (15). FXYD proteins have an extracellular NH2 terminus containing the signature PFXYD motif, a single transmembrane (TM) domain, and a cytoplasmic COOH terminus. They are distributed either in excitable tissues or organs involved in solute and fluid transport. Members in the FXYD family are ...
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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1967
ISSN: 1540-7748,0022-1295
DOI: 10.1085/jgp.50.6.185