title: Effects of AH-1058, a new antiarrhythmic drug, on experimental arrhythmias and cardiac membrane currents.
abstract: AH-1058 is a newly synthesized antiarrhythmic agent. We investigated the antiarrhythmic and electrophysiological effects of AH-1058 in experimental arrhythmia models and isolated cardiomyocytes. In the ouabain-induced arrhythmia model of the guinea pig, pretreatment with AH-1058 (0.1-0.3 mg/kg, i.v.) delayed the appearance of premature ventricular complex (PVC) and ventricular fibrillation (VF) induced by intravenous infusion of ouabain. However, disopyramide (10 mg/kg, i.v.) delayed only that of PVC, and verapamil (1 mg/kg, i.v.) failed to affect the ouabain-induced ventricular arrhythmias. In the reperfusion-induced arrhythmia model of the rat, in which 5-min coronary occlusion and 10-min reperfusion were produced, AH-1058 (0.1-0.3 mg/kg, i.v.) inhibited the incidence of both ventricular tachycardia (VT) and VF, whereas disopyramide (5 mg/kg, i.v.) inhibited only reperfusion-induced VF. On the other hand, a higher dose of AH-1058 (1 mg/kg, i.v.) did not affect the aconitine-induced arrhythmias in rats, which were inhibited by disopyramide (5 mg/kg, i.v.). We also confirmed oral activity of AH-1058 in the reperfusion-induced arrhythmia model of the rat. AH-1058, at doses of 2-4 mg/kg, dose-dependently inhibited VT and VF. Electrophysiological experiments with patch-clamp techniques revealed that AH-1058 potently suppressed the L-type Ca2+ currents in isolated cardiomyocytes of the guinea pig. These results suggest that AH-1058 is a potent antiarrhythmic drug having a Ca2+ channel-blocking action. The antiarrhythmic profile of AH-1058 is different from that of disopyramide and verapamil.
authors.affiliation: Pharmaceutical Research Laboratories, Ajinomoto Co., Inc., Kawasaki, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Takahara
authors.forename: H
authors.initials: H
authors.lastname: Uneyama
authors.forename: N
authors.initials: N
authors.lastname: Sasaki
authors.forename: H
authors.initials: H
authors.lastname: Ueda
authors.forename: H
authors.initials: H
authors.lastname: Dohmoto
authors.forename: M
authors.initials: M
authors.lastname: Shoji
authors.forename: Y
authors.initials: Y
authors.lastname: Hara
authors.forename: H
authors.initials: H
authors.lastname: Nakaya
authors.forename: R
authors.initials: R
authors.lastname: Yoshimoto
mesh_terms: D000157:Aconitine / Q000494:pharmacology; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000188:drug therapy*; D001643:Bridged Bicyclo Compounds / Q000494:pharmacology / Q000627:therapeutic use*; D004594:Electrophysiology; D005260:Female; D006168:Guinea Pigs; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects*; D010042:Ouabain / Q000494:pharmacology; D010477:Perfusion; D010880:Piperidines / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000889:Anti-Arrhythmia Agents; D001643:Bridged Bicyclo Compounds; D010880:Piperidines; D010042:Ouabain; D000157:Aconitine; C119283:AH 1058