Animal experiment:

Rabbits[1]The drug is injected intravenously into rabbits. Experiments on the isolated ears of the rabbits are carried out by the Kravkov--Pisemskii method. The effect of tropaphen on the ear vessels of the intact rabbit is judged by the changes in the temperature of the ear. The temperature is measured by means of an electrothermometer, the detector of which is fixed to the internal surface of the ear. The dilation of the auricular vessels is also examined under the microscope, observations being made on the lumen of the marginal artery and vein[1].

Tropodifene (Tropaphen) is an α-Adrenergic receptor inhibitor.

Tropaphen has a beneficial effect on hypertension. The therapeutic effect of this preparation is more constant in diseases accompanied by spasm of the peripheral vessels. Tropaphen has a very marked adrenolytic and vasodilator action. It greatly lowers the tone of the peripheral vessels. The preparation is effective starting with a dose of 0.1 mg/kg. After injection of the drug in a dose of 0.25 mg/kg, a considerable and gradually progressive decrease in the perfusion pressure takes place. The pressure falls by 30-35% and remained at a low level for 90-100 min. With a dose of tropaphen of 0.5 mg/kg, the perfusion pressure falls by 40-45% and remains low for 120 min or more. Strong vasodilatation is also observed after injection of tropaphen into intact rabbits[1].

[1]. Mashkovskii MD, et al. The action of tropaphen on the peripheral vessels. Pharmacology. 1964. 58. 69-71.