title: Isometric contractions of cardiac Purkyne fibers in Na-free, Sr-Tyrode.
mesh_terms: D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D006329:Heart Conduction System / Q000502:physiology*; D066298:In Vitro Techniques; D007552:Isotonic Solutions; D008345:Manganese / Q000494:pharmacology; D009119:Muscle Contraction; D012964:Sodium / Q000502:physiology
chemical_list: D007552:Isotonic Solutions; D008345:Manganese; D012964:Sodium; D002118:Calcium