Comparison of the cardiovascular action of isoproterenol,dopamine, and dobutamine in the neonatal and mature dog

Summary To determine if there are age-related differences of cardiovascular responses to isoproterenol, dopamine hydrochloride, and dobutamine hydrochloride, we recorded cardiac output, renal artery blood flow, central aortic blood pressure, and heart rate in 11 anesthetized puppies ranging in age from 0 to 10 days and in five adult dogs during incremental infusion of isoproterenol (0.05 to 1.25μg/kg/min), dopamine (2 to 50μg/kg/min), and dobutamine (2 to 50μg/kg/min). Isoproterenol decreased systemic arterial mean blood pressure and renal blood flow more in adult dogs than in puppies. Cardiac output was increased in both age groups, but the increase was more marked in adults than in puppies. Heart rate increased similarly in puppies and adults. Dopamine increased systemic arterial mean blood pressure, heart rate, renal blood flow, and cardiac output in both puppies and adult dogs, but the increase of cardiac output was more marked in adult dogs than in puppies. Dobutamine significantly increased systemic arterial mean blood pressure, cardiac output, and renal blood flow in adult dogs but not in puppies. Heart rate increased in both groups of dogs. This study demonstrates age-related differences in the response of the cardiovascular system of anesthetized dogs to isoproterenol, dopamine, and dobutamine. This material was developed by the Section of Myocardial Biology of the National Heart and Blood Vessel Research and Demonstration Center, Baylor College of Medicine, a grant-supported research project of the National Heart, Lung, and Blood Institute, National Institutes of Health, grant HL 17269 and contract HV-52998. Supported in part by grant HL-5756 from the National Institutes of Health. Dr. Driscoll is recipient of Young Investigator's Award 1-R23 H622309-01 from the National Heart, Lung, and Blood Institute. Dr. Gillette is recipient of National Institutes of Health Research Career Development Award HL00571. Presented at the Scientific Sessions of the American Academy of Pediatrics, Section of Cardiology, New York, New York, November 1977