Characteristic force-velocity equation of rat heart muscle

Abstract

Shortening velocities were measured for in vitro rat left ventricular trabeculae carneae preparations stimulated to contract isotonically with different loads, and at temperatures from 20 C to 35 C. The data obtained were used to derive the heat of shortening constant, a, the velocity constant, b, and the maximum isometric tetanic tension term, P₀, of the characteristic force-velocity equation. The study showed that the derived constants a and P₀ statistically did not vary with temperature, but that the velocity constant b increased linearly as temperature increased. Differences between cardiac and skeletal muscle are discussed.