Effects of high-intensity training and acute exercise on in vitro function of rat sarcoplasmic reticulum.
To evaluate the effects of high-intensity training and/or a single bout of exercise on in vitro function of the sarcoplasmic reticulum (SR), the rats were subjected to 8 weeks of interval running program (final training: 2.5-min running x 4 sets per day, 50 m/min at 10% incline). Following training, SR function, i.e., Ca2+-ATPase activity and Ca2+-uptake and release rates, was examined in homogenates of the superficial region of the vastus lateralis muscle from rats subjected to a single bout of treadmill running (50 m/min at 10% incline) for 2.5 min or to exhaustion. Training brought about a 12.4% increase (P < 0.05) in SR Ca2+-uptake rate in rested muscles. This change was not accompanied by alterations in Ca2+-ATPase activity, Ca2+-release rate, Ca2+ dependence of enzyme and protein contents of Ca2+-ATPase and ryanodine receptor. A single bout of high-intensity exercise to exhaustion evoked significant reductions (P < 0.05) in SR function, irrespective of whether or not the animals were trained. For 2.5-min run and exhausted rats, no differences existed between SR functions of untrained and trained muscles. These data suggest that high-intensity training may be capable of enhancing SR Ca2+-sequestering ability, and may not protect against decreasing SR function with high-intensity exercise.
Matsunaga
Satoshi
S
Research Center for Urban Health and Sports, Osaka City University, Sugimoto, Osaka-shi, Osaka, 558-8585, Japan.
Yamada
Takashi
T
Mishima
Takaaki
T
Sakamoto
Makoto
M
Sugiyama
Minako
M
Wada
Masanobu
M
D000818:Animals; D001797:Blood Protein Electrophoresis; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D018482:Muscle, Skeletal / Q000201:enzymology / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism / Q000502:physiology; D012519:Sarcoplasmic Reticulum / Q000201:enzymology / Q000502:physiology*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism
D019837:Ryanodine Receptor Calcium Release Channel; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D018995:Myosin Heavy Chains; D000252:Calcium-Transporting ATPases; D002118:Calcium