Caffeine and theophylline contractures in tonic skeletal muscle fibers of the frog.

@article{Muiz1992CaffeineAT,
  title={Caffeine and theophylline contractures in tonic skeletal muscle fibers of the frog.},
  author={Jes{\'u}s Mu{\~n}iz and Miguel Huerta and Juan C. Due{\~n}as and X{\'o}chitl Trujillo and Alejandro Manuel Elizalde},
  journal={The Japanese journal of physiology},
  year={1992},
  volume={42 5},
  pages={711-20}
}
Caffeine and theophylline evoke maintained tension in tonic skeletal muscle fibers of the frog. Their effects depended upon concentrations ranging from 0.5 to 14 mM. The resting potential of tonic skeletal fiber was unaffected by caffeine or theophylline (4 mM). Caffeine and theophylline contractures have a peak tension followed by a sustained tension, which recovered spontaneously when returned to normal solution. The peak tension and total tension (the area under tension-time curve) were… CONTINUE READING