Paraxanthine, a caffeine metabolite, dose dependently increases [Ca(2+)](i) in skeletal muscle.

@article{Hawke2000ParaxanthineAC,
  title={Paraxanthine, a caffeine metabolite, dose dependently increases [Ca(2+)](i) in skeletal muscle.},
  author={Thomas J. Hawke and David G Allen and M. Lindinger},
  journal={Journal of applied physiology},
  year={2000},
  volume={89 6},
  pages={
          2312-7
        },
  url={https://api.semanticscholar.org/CorpusID:11369121}
}
It is concluded that physiological and low pharmacological concentrations of paraxanthine result in transient, subcontracture increases in [Ca(2+)](i) in resting skeletal muscle, the magnitude of which is related to parax anthine concentration.
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