To test whether a potent @entity6708 -specific phosphodiesterase inhibitor, @entity69542 , is a selective pulmonary vasodilator in @entity120 , we studied its acute hemodynamic effects in conscious, chronically @entity519 pulmonary @entity101 @entity35 . @entity120 was induced by keeping adult @entity35 in a hypobaric chamber for 3 weeks. Two days after catheterization. E 4021 was injected intravenously at doses of 3, 10, 30, 100, 300, and 1,000 micrograms/kg at 10-min intervals. E 4021 caused significant decreases in mean pulmonary arterial pressure of 11 +/- 5, 12 +/- 6, and 18 +/- 5% at doses of 100, 300, and 1,000 micrograms/kg, respectively. In contrast to its depressor effect on mean pulmonary arterial pressure, E 4021 decreased mean systemic arterial pressure significantly (by 9 +/- 2%) at a dose of 1,000 micrograms/kg only. Heart rate and cardiac output were unchanged after the administration of E 4021. Tissue @entity6708 -specific phosphodiesterase activity was markedly higher in lung than in aorta. These results indicate that E 4021 is a relatively selective pulmonary vasodilator in chronically @entity519 pulmonary @entity101 @entity35 . We conclude E 4021 may be useful for the treatment of @entity120 .

[E 4021, a @entity6708 phosphodiesterase inhibitor, is a selective pulmonary vasodilator in chronically @entity519 pulmonary @entity101 XXXX ].

@entity6708 :: ('CHEBI:16356', 'Chemical') :: ['cGMP'] @entity101 :: ('MESH:D006973', 'Disease') :: ['hypertensive'] @entity120 :: ('MESH:D006976', 'Disease') :: ['pulmonary hypertension', 'Chronically hypoxic pulmonary hypertension'] @entity519 :: ('MESH:D000860', 'Disease') :: ['hypoxic'] @entity69542 :: ('MESH:C091517', 'Chemical') :: ['E 4021'] @entity35 :: ('10116', 'Species') :: ['Sprague-Dawley rats', 'rats']
@entity35 :: (10116,Species) :: ['rats']
