title: Effects of bepridil on regional myocardial ischemia and comparison with verapamil.
abstract: This study was designed to assess the efficacy of bepridil in reducing regional myocardial ischemia and to compare its efficacy with that of verapamil. Forty-five anesthetized, open-chest dogs were subjected to three 5-minute occlusions of the left anterior descending coronary artery (LAD), each followed by 45 minutes of reperfusion. Eleven dogs (group 1) served as controls. In 10 dogs, bepridil, 5 mg/kg, was administered before the third occlusion (group 2). In 11 dogs, verapamil was administered before the third occlusion (group 3). In each dog, on-line intramyocardial hydrogen ion concentration and carbon dioxide tension were measured in the myocardial segment supplied by the LAD. Regional myocardial contractility was assessed in this area with 2 pairs of ultrasonic crystals inserted to determine percent segmental shortening. Regional myocardial blood flow was determined during each occlusion by washout of xenon-127. The increase in hydrogen ion concentration and carbon dioxide tension did not change from occlusion 2 to occlusion 3 in the control group. Both bepridil and verapamil elicited a significant reduction in the extent of regional ischemia, evidenced by a reduction in the accumulation of hydrogen ions, in occlusion 3 vs occlusion 2. Systolic bulging occurred during all occlusions and the periods of reperfusion were not sufficient to allow complete recovery of regional function. Bepridil and verapamil each caused a significant increase in percent segmental shortening (both p less than 0.025), and verapamil effected a significant improvement of function during occlusion 3 compared with occlusion 2.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D015764:Bepridil; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002245:Carbon Dioxide / Q000378:metabolism; D003326:Coronary Circulation / Q000187:drug effects*; D003327:Coronary Disease / Q000503:physiopathology*; D004285:Dogs; D006863:Hydrogen-Ion Concentration; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D011759:Pyrrolidines / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology*
chemical_list: D002121:Calcium Channel Blockers; D011759:Pyrrolidines; D002245:Carbon Dioxide; D015764:Bepridil; D014700:Verapamil