Induction of a fatigue-resistant phenotype in rabbit fast muscle by small daily amounts of stimulation.
We have shown that fatigue resistance can be induced in rabbit tibialis anterior (TA) muscles without excessive power loss by continuous stimulation at low frequencies, such as 5 Hz, and that the same result is obtained by delivering a 10-Hz pattern in equal on/off periods. Here we ask whether the same phenotype could be produced with daily amounts of stimulation that would be more appropriate for clinical use. We stimulated rabbit TA muscles for 6 wk, alternating fixed 30-min on periods of stimulation at 10 Hz with off periods of different duration. All patterns transformed fast-glycolytic fibers into fast-oxidative fibers. The muscles had fatigue-resistant properties but retained a higher contractile speed and power production than muscles transformed completely to the slow-oxidative type. We conclude that in the rabbit as little as one 30-min period of stimulation in 24 h can result in a substantial increase in the resistance of the muscle to fatigue.
Lopez-Guajardo
A
A
Department of Human Anatomy and Cell Biology, University of Liverpool, New Medical School, Liverpool L69 3GE, United Kingdom.
Sutherland
H
H
Jarvis
J C
JC
Salmons
S
S
D000818:Animals; D004558:Electric Stimulation; D005260:Female; D006019:Glycolysis; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D018656:Muscle Fibers, Fast-Twitch / Q000166:cytology / Q000502:physiology*; D018657:Muscle Fibers, Slow-Twitch / Q000166:cytology / Q000502:physiology; D018482:Muscle, Skeletal / Q000166:cytology / Q000502:physiology*; D018994:Myosin Light Chains / Q000032:analysis; D009246:NADH Tetrazolium Reductase / Q000032:analysis; D010101:Oxygen Consumption; D020033:Protein Isoforms / Q000032:analysis; D011817:Rabbits; D013997:Time Factors
D018994:Myosin Light Chains; D020033:Protein Isoforms; D009246:NADH Tetrazolium Reductase