Effect of intracoronary captopril on coronary blood flow and regional myocardial function in dogs.
To evaluate the cardiac effect of an inhibitor of angiotensin-converting enzyme, the effect of intracoronary (i.c.) captopril on coronary blood flow and regional myocardial function was examined in the anesthetized open-chest dog. Blood flow of the left circumflex coronary artery (LCX), left ventricular pressure (LVP), aortic pressure (AoP) and regional myocardial segment length were measured continuously. Captopril i.v. (0.3 mg/kg) produced an immediate reduction in AoP and an increase in percent shortening of myocardial segments followed by a decrease in coronary vascular resistance and increases in heart rate and LVdP/dt. Reductions in LCX flow induced by i.c. angiotensin were attenuated and i.c. bradykinin-induced increases in LCX flow were augmented after captopril. On the contrary, i.c. infusion of captopril (0.01 mg/min) into the LCX caused no change in hemodynamic variables and myocardial shortening although responses to angiotensin I and bradykinin were markedly modified. These results suggest that captopril may have no direct cardiac effect.
D000109:Acetylcholine / Q000494:pharmacology; D000803:Angiotensin I / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002216:Captopril / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D006321:Heart / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D011392:Proline / Q000031:analogs & derivatives*
D000804:Angiotensin II; D000803:Angiotensin I; D011392:Proline; D002216:Captopril; D000109:Acetylcholine; D001920:Bradykinin