title: Comparison of the effects of a benzotriazinium iodide and quinidine on guinea-pig heart.
abstract: 1 The actions of 2-n-propyl-4-p-tolylamino-1,2,3-benzotriazinium iodide (TnPBI) and quinidine were compared on guinea-pig heart preparations. 2 Quinidine had negative inotropic and chronotropic effects on guinea-pig isolated atria and on Langendorff hearts: TnPBI had negative inotropic and chronotropic effects on Langendorff hearts, but showed a positive inotropic effect on isolated atria at low dose levels. 3 Both quinidine and TnPBI increased the effective refractory period of guinea-pig atrial preparations. 4 The effects of TnPBI on transmembrane action potentials indicated a mixed class I and class III action according to the classification of Vaughan Williams (1970). 5 These effects are discussed in relation to the antiarrhythmic actions of TnPBI.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D003864:Depression, Chemical; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D011802:Quinidine / Q000494:pharmacology*; D012032:Refractory Period, Electrophysiological / Q000187:drug effects; D014227:Triazines / Q000494:pharmacology*
chemical_list: D000889:Anti-Arrhythmia Agents; D014227:Triazines; C015481:2-n-propyl-4-4-tolylamino-1,2,3-benzotriazinium; D011802:Quinidine