title: Vasodilator and inotropic effects of the antiarrhythmic drug melperone.
abstract: We investigated the hemodynamic and inotropic effects of the new class III antiarrhythmic drug melperone. In eight pentobarbital-anesthetized dogs, the effects of intravenous melperone 0.5, 2.5, and 12.5 mg/kg-1 were tested. During atrial pacing we measured cardiac output (CO), mean aortic blood pressure (MAP), right (RV) and left (LV) ventricular pressures, and LV dP/dt. In six RV papillary muscles isolated from cats and suspended in a muscle bath containing Krebs-Henseleit solution, we studied the direct effects of melperone 10(8)-5 X 10(-5) M. Administration of melperone decreased total peripheral resistance, MAP, RV and LV systolic and end-diastolic pressures, while CO remained unchanged. Melperone increased LV dP/dtmax. The contractile force (F) and dF/dtmax of the isolated ventricular muscle preparations increased slightly with increasing concentrations of melperone, up to 10(-5) M. In conclusion, melperone has vasodilator and slight positive inotropic effects in addition to its class III antiarrhythmic effect.
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D002090:Butyrophenones / Q000494:pharmacology*; D004285:Dogs; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects; D014665:Vasodilator Agents
chemical_list: D000889:Anti-Arrhythmia Agents; D002090:Butyrophenones; D005230:Fatty Acids, Nonesterified; D014665:Vasodilator Agents; C008522:metylperon