title: Pharmacology of SCH00013: a novel Ca2+ sensitizer.
abstract: Cardiotonic agents that facilitate cardiac pump function by direct improvement of contractile dysfunction are indispensable for the treatment of hemodynamic disorders in acute myocardial failure and the aggravating phase of congestive heart failure. Cardiotonic agents currently available for the treatment of hemodynamic crisis in congestive heart failure are catecholamines, selective phosphodiesterase (PDE) III inhibitors and digitalis, all of which are Ca2+ mobilizers. Considering the number of serious adverse effects of these clinically available cardiotonic agents, development of agents that act via a novel mechanism of action may contribute to the progress of pharmacotherapy of congestive heart failure. Ca2+ sensitizers that act by increasing in myofilament Ca2+ sensitivity may be able to overcome the disadvantage of Ca2+ mobilizers. Ca2+ sensitizers do not increase activation energy, do not produce Ca2+ overload and may be effective even under pathophysiological states such as acidosis, myocardial stunning and heart failure. SCH00013 ((4,5-dihydro-6-[1-[2-hydroxy-2-(4-cyanophenyl)ethyl]-1,2,5,6-tetrahydropyrido-4-yl]pyridazin-3(2H)-one)) is a novel Ca2+ sensitizer that elicits a moderate positive inotropic effect without significant alteration of Ca2+ transients. SCH00013 does not have a positive chronotropic effect and has a weak PDE III inhibitory action and class III antiarrhythmic action. SCH00013 prolonged the survival in a animal heart failure model with genetic cardiomyopathy. The oral bioavailability of SCH00013 is high and equivalent to that via intravenous administration. The unique pharmacological profiles of SCH00013 imply that this agent may be potentially beneficial for pharmacotherapy of contractile dysfunction in congestive heart failure.
authors.affiliation: Department of Pharmacology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Endoh
authors.forename: H
authors.initials: H
authors.lastname: Sugawara
authors.forename: M
authors.initials: M
authors.lastname: Mineshima
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002316:Cardiotonic Agents / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D051668:Delayed Rectifier Potassium Channels; D004095:Dihydropyridines / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D006333:Heart Failure / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D011724:Pyridazines / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013237:Stereoisomerism; D013268:Stimulation, Chemical; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D000889:Anti-Arrhythmia Agents; D002316:Cardiotonic Agents; D051668:Delayed Rectifier Potassium Channels; D004095:Dihydropyridines; D010726:Phosphodiesterase Inhibitors; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D011724:Pyridazines; C115124:Sch 00013; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium