title: Protective effect of cycloprotobuxine-A against cardiac arrhythmias induced by ouabain.
abstract: Cycloprotobuxine-A (CPB-A) 1-4 mg.kg-1 iv increased the dose of ouabain required to induce ventricular arrhythmias in guinea pigs. At the equitoxic doses (1/50 LD50), CPB-A was more potent than cyclovirobuxine-D and amiodarone. Pretreatment with reserpine (5 mg.kg-1 ip), vagotomy or pithing spinal cord did not prevent the action of CPB-A, which indicate that the protective effect of CPB-A may be due to its direct action on myocardium without the involvement of nervous system. In isolated guinea pig ventricular muscles, CPB-A 3 mumol.L-1 consistently decreased the amplitude of oscillatory afterpotentials (OAP) and blocked triggered activity elicited by ouabain. At 30 mumol.L-1, CPB-A abolished the appearance of OAP. It seems that one of the mechanisms for the anti-arrhythmic action of CPB-A was a decrease in the amplitude of OAP.
authors.affiliation: Department of Pharmacology, Fourth Military Medical University, Xi-an, China.
authors.forename: Y X
authors.initials: YX
authors.lastname: Wang
authors.forename: Y H
authors.initials: YH
authors.lastname: Tan
authors.forename: B H
authors.initials: BH
authors.lastname: Sheng
mesh_terms: D000470:Alkaloids / Q000494:pharmacology* / Q000627:therapeutic use; D000638:Amiodarone / Q000494:pharmacology; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D001794:Blood Pressure / Q000187:drug effects; D004594:Electrophysiology; D005260:Female; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D010042:Ouabain
chemical_list: D000470:Alkaloids; D000889:Anti-Arrhythmia Agents; C062783:cycloprotobuxine A; D010042:Ouabain; D000638:Amiodarone