title: Myocardial pharmacodynamics of dopamine, dobutamine, amrinone and isoprenaline compared in the isolated rabbit heart.
abstract: The isolated spontaneously beating rabbit heart was used for comparing the myocardial effects of isoprenaline, dobutamine, dopamine and amrinone. Both isoprenaline and dobutamine produced a progressive concentration-dependent increase in contractility from 100% to a maximum of about 200% (pD2 7.81 and 7.01, respectively) as measured by the increase in isotonic contraction rate. The simultaneous augmentations in contraction amplitude reached maxima of about 127 and 143% (pD2 7.83 and 7.05) for each of the drugs and the heart frequency rose to 202 and 162% (pD2 7.80 and 6.63), respectively. The accompanying oxygen consumption increased from 100 to 194% (pD2 7.70) for isoprenaline and to only 177% (pD2 6.36) for dobutamine. Coronary flow rate rose to 153 and 134%, respectively. Dopamine increased the contraction rate to 181% (pD2 6.26), contraction amplitude to about 122% (pD2 6.25) and heart rate to 162% (pD2, 5.85), while oxygen consumption rose to a maximum of 202% (pD2 5.69). Coronary flow rate rose to 156%. In contrast amrinone produced an unexpected slowly progressing decrease in contraction rate and contraction amplitude to about 66% (pD2 4.45 and 4.01, respectively). Oxygen consumption increased to 159% (pD2 4.10) and coronary flow rate to 210%. The positive inotropic effect of dobutamine thus equalled that of isoprenaline but with a distinct lower concomitant increase in heart frequency and oxygen consumption which may reflect a better myocardial efficiency during the action of dobutamine.
mesh_terms: D000631:Aminopyridines / Q000494:pharmacology*; D000676:Amrinone; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D004280:Dobutamine / Q000494:pharmacology*; D004298:Dopamine / Q000494:pharmacology*; D005260:Female; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D011817:Rabbits
chemical_list: D000631:Aminopyridines; D004280:Dobutamine; D000676:Amrinone; D007545:Isoproterenol; D004298:Dopamine