13 - Effects of Heavy Water on Muscle

Abstract

This chapter discusses the effects of heavy water on muscle. It discusses a study to examine the effect of heavy water on heart, smooth and striated muscle. Tension and surface electroatriograms were recorded from spontaneously beating isolated atria of Xenopus laevis. After a control period in a temperature controlled chamber, the normal frog Ringer's solution was replaced with ones containing D2O in concentrations of 25%, 50%, 75%, and 99.8%. The rate and force of contraction were markedly affected as was observed previously in frog hearts. A noticeable reduction of frequency was observed 50 seconds after immersion in the D2O and the frequency was reduced by 75% within 15 minutes in 75% or 99.8% D2O. Thereafter, the atria in 99.8% D2O either stopped beating or slowed down to 1 beat every 5 or 7 minutes. Similarly a reduction in tension occurred within 50 seconds in D2O. In 99.8% D2O, the tension decreased by more than 90% of its basal value after 2.5 minutes. The maximum reduction in tension occurred in 5 minutes in all concentrations of D2O. In 25% D2O, there was a subsequent rise in tension after 10–20 minutes but it remained 23% below the basal value