Separate and combined use of verapamil, aspirin and captopril in experimental chronic pulmonary hypertension.

In Wistar rats, rendered pulmonary hypertensive by chronic confinement in normobaric "hypoxic cages", impairment of transmembrane transport of calcium by Verapamil and blockage of the action of Angiotensin I converting enzyme by Captopril when applied simultaneously did not show an additive effect in reducing the rise of pulmonary artery pressure and decreasing the augmentation of right ventricular mass. Similarly, the action of Verapamil together with decrease of prostaglandin synthetase activity by Aspirin showed no additive effect. Although in this way the results of the present study failed to give substantial support to the idea of the existence of several mediators of hypoxic pulmonary vasoconstriction, they by no means deny this possibility.