Actions of prostaglandins E1 and F2alpha on isolated intrapulmonary vascular smooth muscle

The effects of PGE1 and PGF2alpha were studied on isolated strips of intrapulmonary arteries and veins from dog, sheep, swine and man. PGF2alpha contracted human arterial strips in a dose-dependent fashion, relaxed slightly sheep arteries and had no effect on dog arteries. Canine, sheep and human venous strips were contracted by PGF2alpha. PGE1 relaxed slightly both veins and arteries from dog and sheep. Human arteries usually contracted slightly and human veins usually relaxed slightly to PGE1. In a limited number of experiments, swine arteries and veins failed to respond to PGF2alpha or PGE1. All the vascular strips contracted well when exposed to NE. These results suggest that the responses of intrapulmonary vessels to PGF2alpha and PGE1 are species-dependent. PGF2alpha generally exhibits a contractile action, especially on veins. PGE1 usually relaxes intrapulmonary vessels. With regard to vessels from man, PGF2alpha is a powerful stimulant while PGE1 produces only small, variable effects.