title: Methylxanthine-induced escalation: a propagated wave phenomenon observed in skeletal muscle developing in culture.
abstract: Relatively low concentrations of methylxanthines increase spontaneous twitching in cultured muscle fibers; they also cause a second activity, escalation, which is the initiation and undiminished propagation of visible waves. The effect on twitching is abolished by depolarizing concentrations of K(+) or by tetrodotoxin; the effect on escalation is not. Escalation is prevented by removal of external Ca(++) or by the addition of tetracaine.
mesh_terms: D000628:Aminophylline / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002642:Chick Embryo; D046508:Culture Techniques; D008564:Membrane Potentials; D008858:Microscopy, Phase-Contrast; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000166:cytology / Q000196:embryology / Q000502:physiology; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology*
chemical_list: D014970:Xanthines; D000628:Aminophylline; D012964:Sodium; D013806:Theophylline; D011188:Potassium; D002118:Calcium