Manipulation of dopamine receptors alters hypoxic pulmonary vasoconstriction in isolated perfused rat lungs.

Using an isolated, perfused rat lung model, we examined the hypoxic pulmonary vasoconstriction (HPV). We studied the alterations in HPV induced by the selective DA1 receptor agonist, fenoldopam, the selective DA1 antagonist, SCH 23390, as well as a combination of these agents. Fenoldopam significantly attenuated HPV. SCH 23390 had no effect on HPV, but was ableto block the effect of fenoldopam. These data confirm the presence of vasodilatory DA1 receptors in the pulmonary vascular bed. The data further suggest that ongoing DA1 activity may be important in counterbalancing some pathologic pulmonary hypertensive states.