title: Procaine-induced positive chronotropic and inotropic responses of the isolated, blood-perfused dog atrium.
abstract: In the isolated, blood-perfused canine atrium preparations, procaine given into the cannulated sinus node artery induced frequently significantly positive chronotropic and inotropic effects at a dose level of 30-1000 microng. Above a dose of 100 microng, initially brief negative chronotropic and inotropic effects were usually observed. Procaine-induced negative effects were not blocked by an adequate dose level of atropine. Procaine-induced positive effects were inhibited by treatment with propranolol but not modified by tetrodotoxin or desmethylimipramine. Procaine suppressed acetylcholine-induced negative chronotropic and inotropic effects. On the other hand, procaine did not block norepinephrine-induced positive inotropic and chronotropic effects. From these results, it is concluded that procaine may have sympathomimetic and atropine-like properties.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D003891:Desipramine / Q000494:pharmacology; D004285:Dogs; D004347:Drug Interactions; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011343:Procaine / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D013268:Stimulation, Chemical; D013779:Tetrodotoxin / Q000494:pharmacology; D014439:Tyramine / Q000494:pharmacology
chemical_list: D013779:Tetrodotoxin; D011343:Procaine; D009538:Nicotine; D001285:Atropine; D011433:Propranolol; D000109:Acetylcholine; D003891:Desipramine; D009638:Norepinephrine; D014439:Tyramine