Cross-Influence of Halothane and Voltage on Intracellular Ca2+ in Isolated Muscle Fibers of Mice Expressing Human RyR1 Mutation Y522S

Abstract

41 C/1h): interestingly mortality rate was dramatically decreased in trained (t) CASQ1-null mice compared to un-trained (un-t) controls: 16% vs. 86%, respectively. In tCASQ1-null mice, the increase in core temperature during exposure to heat-stress (i.e. hyperthermia) was lower than in un-t mice, and their EDL muscles displayed a lowered threshold of response when exposed to increasing [caffeine] during in-vitro contracture test (IVCT). Several other parameters were assessed in muscle samples: aerobic training succeeded in decreasing mitochondrial damage (14.853.9% vs. 752.3%), mitochondrial efficiency by increasing of 34% the cytochrome-c oxidase activity, while decreasing SERCA's and also Ca 2þ -dependent proteolytic activity. Additionally, training also reduced lipid peroxidation (elevated in un-tCASQ1-null mice) in isolated sarcoplasmic reticulum and mitochondria membranes: À45 and À35 %, respectively. In conclusion, aerobic training protects CASQ1null mice from HS, an effect essentially mediated by a significant reduction in oxidative stress and fiber damage.