Blood Flow into the Autotransplanted Canine Lung after Administration of Sympathomimetic Drugs

Abstract

The vascular responses of the autotransplanted lung to noradrenaline, isoprenaline and tyramine were studied on anaesthetized mongrel dogs, which had undergone left lung autotransplantation 2 to 27 months previously. The responses were estimated by measuring the distribution of pulmonary blood flow between the intact and autotransplanted lung before and after the drug administration.

Noradrenaline shifted slightly the blood flow towards ths autotransplanted left lung. Isoprenaline tended to change the blood flow in the opposite direction, but the average change was not statistically significant. Tyramine did not modify the distribution of the blood flow. The doses given produced profound changes in the aortic pressure and pulse rate, suggesting that the weak responses of the pulmonary circulation were not due to too small doses. Thus, the autotransplanted lung and the intact lung differed very little in their responses to sympathomimetic drugs.