[ATPase activity of rabbit skeletal muscles actomyosin complex under ultrasound effect].

Influence of continuous and impulsive ultrasound 0.05; 0.2; 0.4; 0.7 and 1.0 W/cm2 on ATPase activity of rabbit skeletal muscle actomyosin has been investigated in this work. It has been shown that most changes of Mg2+, Ca(2+)-ATPase activity are observed under 0.2 and 0.4 W/cm2 continuous ultrasound. K(+)-ATPase activity is inhibited by continuous ultrasound of all intensities studied. Impulsive 2 and 10 ms ultrasound did not change the Mg2+,Ca(2+)-ATPase activity. While K(+)-activity is reliably changed only under impulsive 0.7 and 1.0 W/cm2 ultrasound that can be explained by the thermal effect. It has been determined, when studying the reconstructed actomyosin with sound troponin complex, that troponin complex is the most ultrasound sensitive constituent of actomyosin.

[Effect of continuous and impulsive ultrasound on actomyosin superprecipitation reaction from rabbit skeletal muscles].

A comparative study of the effect of continuous and impulsive (2 ms) ultrasound regimes on actomyosin superprecipitation reaction of the rabbit skeletal muscles was carried out. From the obtained kinetic curves the value of superprecipitation (D(m) - D(00)), time t1/2, which required to achieve a half its value was determined, and the normalized maximal rate of this reaction V(n) was calculated as well. It is shown that continuous ultrasound with intensities 0.7 W/cm2 and impulsive ultrasound--of 0.4 W/cm2 produced the most pronounced effect (value of superprecipitation and V(n) were maximal). The actomyosin superprecipitation value under continuous and impulsive ultrasound with intensity 1 W/cm2 relative to control and all other applied intensities was most decreased. It is caused perhaps thermal influence of the ultrasound. Thus the obtained data give every reason to assume, that impulsive ultrasound causes changes of adaptive character in actomyosin because the interrupted regime of the ultrasound signal.