title: Effects of KB-R9032, a new Na+/H+ exchange inhibitor, on canine coronary occlusion/reperfusion-induced ventricular arrhythmias.
abstract: We investigated the effects of KB-R9032 (N-(4-isopropyl-2,2-dimethyl-3-oxo-3,4-dihydro-2H-benzo[1,4]oxazine-6-carbonyl) guanidine methanesulfonate), a new Na(+)/H(+) exchange inhibitor, on a coronary artery occlusion/reperfusion-induced arrhythmia model in pentobarbital anesthetized dogs. KB-R9032 reduced the number of ventricular premature contractions seen during the coronary occlusion, while it did not alter the heart rate, mean blood pressure, or electrocardiographic parameters (PR, QRS, or QTc interval). KB-R9032 also decreased the incidence of fatal ventricular fibrillation during coronary artery occlusion and/or after reperfusion. These antiarrhythmic effects were observed not only in the pre-ischemic administration group, but also in the group given KB-R9032 at the 15th min of the 30-min occlusion. These findings support the view that Na(+)/H(+) exchanger may play an important role in inducing coronary ischemia/reperfusion arrhythmias. This suggests that the use of Na(+)/H(+) exchange inhibitors, such as KB-R9032, may be an effective clinical approach to suppress sudden cardiac death due to acute myocardial ischemia/reperfusion such as during coronary bypass surgery, cardiac valve surgery, or percutaneous transluminal coronary angioplasty.
authors.affiliation: Department of Pharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110, Shimogato, Tamaho, Nakakoma, Yamanashi 409-3898, Japan. chikaomi_yamada@dsup.co.jp
authors.forename: Chikaomi
authors.initials: C
authors.lastname: Yamada
authors.forename: YiXue
authors.initials: Y
authors.lastname: Xue
authors.forename: Daisuke
authors.initials: D
authors.lastname: Chino
authors.forename: Keitaro
authors.initials: K
authors.lastname: Hashimoto
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology / Q000517:prevention & control*; D003327:Coronary Disease / Q000517:prevention & control*; D004285:Dogs; D005260:Female; D006146:Guanidines / Q000737:chemistry / Q000494:pharmacology*; D008297:Male; D015394:Molecular Structure; D017202:Myocardial Ischemia / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology / Q000517:prevention & control*; D010078:Oxazines / Q000737:chemistry / Q000494:pharmacology*; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors*; D014693:Ventricular Fibrillation / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control
chemical_list: D006146:Guanidines; C419877:N-(4-isopropyl-2,2-dimethyl-3-oxo-3,4-dihydro-2H-benzo(1,4)oxazine-6-carbonyl)guanidine; D010078:Oxazines; D017923:Sodium-Hydrogen Exchangers