[Kinetic characteristics of cross bridges in the heart muscles by a temperature jump method].

Experiments were performed on rat skinned trabecular muscles dissected from the right ventricles. They were activated (pCa = 5.9) at 10 C, 2.

[The relationship between rigidity and strength in the skinned fiber of rabbit skeletal muscle].

In single chemically skinned fibers of the rabbit skeletal muscle in the state of rigour and the calcium activation, the interrelationship between the strength and rigidity, in change of the sarcomeres length from 2.4 to 3.0 microns, of free calcium concentration (pCa = 6.

[Selective pacemaker interruption and disorders of atrial automaticity during induction of lipid peroxidation].

The influence of lipid peroxidation (LPO) inductor H2O2 on spontaneous contractility and electrical activity of the right atrium was studied. LPO induction caused positive inotropic catecholamine-like effect, followed by brady-arrhythmia with the action of potential prolongation, blockade of electrical activity and atrial arrest. Electrical pacing during atrial arrest caused regular contractions of the same force as before electrical activity blockade.

[Nature of the "length-force" relationship in mammalian heart muscle].

Alteration of myocardial contractile state (a transitional process) is shown to be associated with changes of muscle length or with 3-min pause. The drugs which block the propagation of AP along the T-tubular system, induce a less obvious response of the lengthening alone. An increase of the muscle length seems to lead to improvement of propagation along the T-tubular system and to involve "additional" functional units.

[Static and dynamic components of length-dependent regulation of contraction of the atrial and ventricular myocardium].

The influence of changes in length of the frog isolated atrium and ventriculus upon the isometric twitches was investigated. The length-tension relationship of the first contraction following the step of stretch was independent of the inotropic agents (Ca20+, adrenaline). The stretch to 0,35 induced the 5.

[Inotropic effect of rhythm dispersion].

The influence of rhythm dispersion on the mean amplitude of rat and rabbit papillary muscle contractions and isovolumic contractions of canine heart has been investigated. In rabbit ventricular myocardium which shows a steep force-frequency relationship in the 0.3--1.