Further Observations on the Circulatory Actions of Digitalis and Strophanthus with Special Reference to the Liver, and Comparisons with Histamine and Epinephrine.

In a previous paper (1) it was shown that digitalis in dogs caused a fall in venous pressure at the time when the minute volume flow of blood was diminished. This fall in venous pressure, and hence in return flow of blood to the heart, was correlated with a peripheral vasocontrictor action of the digitalis. It was indicated that constriction of the hepatic veins was the major factor in causing a redistribution of blood, with pooling in the splanchnic area. This venous action of digitalis agreed with results on the perfused liver and on excised veins reported in the literature. Kobert (2), in 1886, and Lampe and Mehes (3), in 1926, demonstrated that digitalis and allied glucosides caused a marked constriction of the vessels of the perfused liver, and Franklin (4), in 1925, reported constriction of excised veins by digitalis. In our experiments on dogs there was a progressive increase in volume of the liver in-situ and a simultaneous constriction of the intestines after doses of digitalis corresponding to the full therapeutic. Although the significance of these changes in the splanchnic region were appreciated at the time, it was thought that additional data on the state of the portal circulation were desirable, particularly with reference to confirmation or denial of the constrictor action of digitalis on the hepatic veins. In the present paper, therefore, further experiments on this portal mechanism are presented, the results with digitalis being compared and correlated with those with histamine and epinephrine as controls.