Effects of pyridoxalated hemoglobin polyoxyethylene conjugate(PHP) and stroma free hemoglobin(SFH) on pulmonary vascular responsiveness to various vasoactive substances in isolated perfused rat lungs.
Pulmonary vascular responsiveness to norepinephrine(NE), angiotensin-II (ANG-II), acetylcholine(ACh) and nitroglycerin (NG) was examined in isolated perfused rat lungs. The lungs were perfused with pyridoxalated hemoglobin polyoxyethylene conjugate (PHP), a newly introduced modified hemoglobin, stroma free hemoglobin (SFH) or hydroxyethyl starch (HES) at a constant flow rate. Perfusion pressure (PP) and intra-tracheal pressure (ITP) were measured. Effects of intrapulmonary arterial injection of NE, ANG-II, ACh and NG on PP were examined. NE and ANG-II produced a dose dependent increase in PP in all groups. The response to NE in PHP or SFH perfused group was significantly greater than that in HES-perfused group. ACh induced a dose dependent decrease in PP in HES and PHP groups, while in the SFH group, ACh produced a dose dependent increase in PP. NG produced a dose dependent decrease in all groups. Results showed that stroma free hemoglobin (SFH) inhibits relaxation induced by endothelium-derived relaxation factor (EDRF), but PHP dose not exert inhibitory action on vascular relaxation induced by EDRF.
Gotoh
K
K
Department of Pharmacology and Anesthesiology, Kumamoto University Medical School, Japan.
Morioka
T
T
Nishi
K
K
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001802:Blood Substitutes / Q000494:pharmacology*; D006454:Hemoglobins / Q000494:pharmacology*; D066298:In Vitro Techniques; D008168:Lung / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology; D010477:Perfusion; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011652:Pulmonary Circulation / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D014664:Vasodilation / Q000187:drug effects
D001802:Blood Substitutes; D006454:Hemoglobins; C016484:hemoglobin, stroma free; C050907:pyridoxalated-hemoglobin-polyethylene glycol conjugate; D009569:Nitric Oxide; D011092:Polyethylene Glycols