title: The inhibitory effects of carvedilol against arrhythmias induced by coronary reperfusion in anesthetized rats.
abstract: BACKGROUND
  Previous study has shown the antiarrhythmic effects of carvedilol on isolated rat hearts, but little is known about the mechanism of this protective action. This article examines the inhibitory effect of carvedilol against arrhythmias induced by reperfusion in anesthetized rats. In addition, the results are compared with those with propranolol, superoxide dismutase (SOD) plus catalase, and a combination of both in order to elucidate the mechanism of the protective actions.
  
  
  METHODS
  Ninety percent of the rats in the control group showed lethal ventricular fibrillation (VF). Carvedilol at the doses of 0.03, 0.1, and 0.3 mg/kg significantly reduced the incidence of lethal VF to 0%, 0%, and 10%, respectively (P <.05). In contrast, propranolol at the doses of 0.3, 1.0, and 3.0 mg/kg and SOD (35,000 units/kg) plus catalase (400,000 units/kg) did not reduce the incidence of lethal VF (80%, 60%, 70%, and 70%, respectively). However, administration of a combination of propranolol (1.0 mg/kg) and SOD plus catalase completely inhibited the occurrence of lethal VF to 0% (P<.05).
  
  
  CONCLUSIONS
  These results indicate that carvedilol has the inhibitory effect against reperfusion arrhythmias in rats and suggest that the mechanism of action of this compound is related to the combined effects of beta-blocking and antioxidant.
authors.affiliation: Second Department of Internal Medicine and the Department of Human Science Yamanashi Medical University, Tamaho, Yamanashi, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Takusagawa
authors.forename: S
authors.initials: S
authors.lastname: Komori
authors.forename: K
authors.initials: K
authors.lastname: Matsumura
authors.forename: M
authors.initials: M
authors.lastname: Osada
authors.forename: I
authors.initials: I
authors.lastname: Kohno
authors.forename: K
authors.initials: K
authors.lastname: Umetani
authors.forename: T
authors.initials: T
authors.lastname: Ishihara
authors.forename: T
authors.initials: T
authors.lastname: Sawanobori
authors.forename: H
authors.initials: H
authors.lastname: Ijiri
authors.forename: K
authors.initials: K
authors.lastname: Tamura
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D000768:Anesthesia, General; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000188:drug therapy* / Q000209:etiology; D002227:Carbazoles / Q000008:administration & dosage / Q000494:pharmacology*; D000077261:Carvedilol; D002374:Catalase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D011412:Propanolamines / Q000008:administration & dosage / Q000494:pharmacology*; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D011433:Propranolol; D002374:Catalase; D013482:Superoxide Dismutase