Vasorelaxant effects of atrial peptide II on isolated human pulmonary muscle preparations.

Isolated human pulmonary arterial preparations were approximately 10-fold more sensitive to atrial peptide II than venous preparations (pD2 values: 7.11 +/- 0.14 and 6.17 +/- 0.14, respectively). Atrial peptide II did not relax isolated human bronchial muscle preparations (pD2 value: greater than 5.5). These data demonstrate that atrial peptide II is a selective relaxant agent in isolated human pulmonary vascular muscle preparations with no effect on isolated human airway muscle preparations.