Effect of xamoterol, a beta 1-adrenoceptor partial agonist, on myocardial pH decreased by coronary occlusion in dogs.
The effect of xamoterol on ischemic myocardial pH was examined in dogs. Partial occlusion of the left anterior descending coronary artery (LAD) decreased myocardial pH from 7.52-7.63 to 6.80-6.85. Xamoterol was injected intravenously 30 min after LAD occlusion that lasted for 90 min. Xamoterol (30 or 70 micrograms/kg) increased the myocardial pH that had been decreased by partial occlusion, the degree of pH increase being greater with 30 micrograms/kg than with 70 micrograms/kg, but at the dose of 200 micrograms/kg it did not increase. In the nonischemic normal heart, xamoterol (30 or 70 micrograms/kg, i.v.) had no marked effect on hemodynamic parameters, but the drug (200 micrograms/kg, i.v.) increased contractile force and heart rate with a transient decrease of myocardial pH. It is concluded that only the small dose (30 or 70 micrograms/kg) of xamoterol is effective in restoring the myocardial pH that has been decreased by partial occlusion of the LAD.
D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000188:drug therapy*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D011412:Propanolamines / Q000627:therapeutic use*; D017307:Xamoterol
D000318:Adrenergic beta-Agonists; D011412:Propanolamines; D017307:Xamoterol