Venotonic activity of escin on the human saphenous vein

The venotonic effects of escin on the human saphenous vein have been evaluated in vitro on histologically normal venous segments obtained during surgical saphenectomy procedures. It is necessary to use the human preparations because of the great variability in the responses of the veins of different species. By using a standard stimulus and fitting the experimental data to the logistic function, we were able to compare the activity of escin with those of the commonly used venotonic agents. Stimulation with escin always induced an increase in venous tone which was constant for a given dose and stable for some time, and maintained for as long as an hour after removal of the substance from the bath. The maximum contraction obtained with escin was similar to those obtained with serotonin and dihydroergotamine, significantly greater than that obtained with acetylcholine or vasopressin. However, the affinity of escin was found to be lower than those of the other substances studied. An increase in venous tone, and therefore a decrease in the volume of the venous district, would be considered a very favorable result to be obtained with a drug which, like escin, is indicated for treatment of venous diseases leading to irreversible dilation.