The effects of MM-creatine kinase deficiency on sustained force production of mouse fast skeletal muscle.
Twitch force production was normal in muscles of mice which lack MM-creatine kinase, but the tetanic force:twitch force ratio was lower than in control muscles (3.60 vs 4.27; P < 0.05). In a series of repeated tetanic contractions the force in the second contraction was already markedly depressed (20-50%), while subsequently only small changes were observed. The effect was greater in exercise that would require a higher metabolic peak flux. The depressed force production was not accompanied by a slowing of relaxation, indicating that enough ATP was present to sustain myofibrillar ATPase and Ca(2+)-ATPase activity.
de Haan
A
A
Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
Koudijs
J C
JC
Wevers
R A
RA
Wieringa
B
B
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003402:Creatine Kinase / Q000172:deficiency* / Q000378:metabolism; D005260:Female; D007527:Isoenzymes; D007537:Isometric Contraction / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D009119:Muscle Contraction / Q000502:physiology*; D009126:Muscle Relaxation; D018482:Muscle, Skeletal / Q000201:enzymology / Q000502:physiology; D005082:Physical Exertion
D007527:Isoenzymes; D000255:Adenosine Triphosphate; D003402:Creatine Kinase; D000251:Adenosine Triphosphatases