Effects of treadmill running on the properties of guinea-pig myosin.

The effects of running training on the structure and function of ventricular myosin of guinea-pigs were studied. No differences in body or heart weights could be detected but the heart-to-body weight relation increased significantly (P less than 0.05) in the trained group. Ca2+ activated and K+ activated ventricular myosin ATPase activities as well as the electrophoretic appearances (SDS-PAGE, pyrophosphate-PAGE) did not change after training. Guinea-pig ventricular myosin in nondissociating conditions showed one band migrating close to rat-V3 isomyosin. The myosins of the trained and untrained animals also showed no immunological difference as determined by the competitive ELISA-test: they both shared antigenic determinants common to rat-V1 isomyosin.