Artificial organs
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We examined the effects of pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) and stroma free hemoglobin (SFH) on vascular responsiveness to various vasoactive substances in isolated perfused rat lungs. The lungs isolated from rats were perfused with 6% PHP, 6% SFH, or 6% hydroxyethylstarch (HES) solution, and the effects of intrapulmonary arterial injection of norepinephrine (NE), angiotensin II (ANG-II), acetylcholine (ACh), and nitroglycerin (NG) were examined by measuring perfusion pressure. NE and ANG-II produced a dose-dependent increase in perfusion pressure in all groups. ⋯ ACh decreased perfusion pressure in both PHP- and HES-perfused groups but increased perfusion pressure in the SFH-perfused group. NG decreased perfusion pressure in all groups. Present results indicate that pulmonary arterial responses to endothelium-derived relaxing factor (EDRF) induced by ACh would not be affected in the presence of PHP.