Effect of deuterium oxide on contraction characteristics and ATPase activity in glycerinated single rabbit skeletal muscle fibers.
We studied the effect of deuterium oxide (D(2)O) on contraction characteristics and ATPase activity of single glycerinated muscle fibers of rabbit psoas. D(2)O increased the maximum isometric force P(0) by about 20%, while the force versus stiffness relation did not change appreciably. The maximum shortening velocity under zero load V(max) did not change appreciably in D(2)O, so that the force-velocity (P-V) curve was scaled depending on the value of P(0). The Mg-ATPase activity of the fibers during generation of steady isometric force P(0) was reduced by about 50% in D(2)O. Based on the Huxley contraction model, these results can be accounted for in terms of D(2)O-induced changes in the rate constants f(1) and g(1) for making and breaking actin-myosin linkages in the isometric condition, in such a way that f(1)/(f(1)+g(1)) increases by about 20%, while (f(1)+g(1)) remains unchanged. The D(2)O effect at the molecular level is discussed in connection with biochemical studies on actomyosin ATPase.
Kobayashi
Takakazu
T
Department of Physiology, School of Medicine, Tokyo University, Tokyo, Japan.
Saeki
Yasutake
Y
Chaen
Shigeru
S
Shirakawa
Ibuki
I
Sugi
Haruo
H
D000251:Adenosine Triphosphatases / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D017666:Deuterium Oxide / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004548:Elasticity; D004789:Enzyme Activation / Q000187:drug effects; D005990:Glycerol / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000187:drug effects* / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology*; D011817:Rabbits; D013314:Stress, Mechanical
D000251:Adenosine Triphosphatases; D017666:Deuterium Oxide; D005990:Glycerol