Effects of nifedipine on isolated human pulmonary vessels

The effects of the Ca-blocker nifedipine on the contractile response to K and NA in isolated human pulmonary vessels were studied. Specimens of macroscopically normal pulmonary vessels, obtained from patients undergoing surgery for lungtumours were carefully dissected and cut into rings. The results suggest that nifedipine, by blocking the entry of extracellular calcium, inhibits K-induced contractions in isolated pulmonary vessels. The effect is more pronounced on K than on NA-induced response in both the pulmonary arteries and veins.