Pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) on the endothelium-dependent relaxation in rat mesenteric arterioles.
Effects of exchange-transfusion with a modified hemoglobin (pyridoxalated hemoglobin polyoxyethylene conjugate; PHP) on diameter of rat mesenteric arterioles responding to various vasoactive substances were examined using the image-splitter television microscopy method. The mesentery of the anesthetized rat was spread over the stage of a microscope and the microvasculature was visualized by transillumination. Exchange-transfusion with a 6%PHP solution (30 ml/kg) was performed and effects of topical application of norepinephrine (NE) and acetylcholine(ACh) on diameter of mesenteric arterioles were examined. By exchange-transfusion with PHP, NE induced a dose-dependent decrease in diameter, while ACh induced a dose-dependent increase in diameter of the arterioles preconstricted by NE. There was no difference in vascular responsiveness to ACh and NE before and after exchange-transfusion with PHP solution. Results suggest that circulating PHP moiety does not exert any action on function of endothelial cell to release endothelium-derived relaxing factor (EDRF) in rat mesenteric microvasculature in situ.
Matsumura
H
H
Department of Pharmacology and Anesthesiology, Kumamoto University Medical School, Japan.
Araki
H
H
Morioka
T
T
Nishi
K
K
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001160:Arterioles / Q000187:drug effects; D001802:Blood Substitutes / Q000633:toxicity*; D005078:Exchange Transfusion, Whole Blood; D006454:Hemoglobins / Q000633:toxicity*; D008638:Mesenteric Arteries / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000633:toxicity*; D051381:Rats; D014664:Vasodilation / Q000187:drug effects*
D001802:Blood Substitutes; D006454:Hemoglobins; C050907:pyridoxalated-hemoglobin-polyethylene glycol conjugate; D009569:Nitric Oxide; D011092:Polyethylene Glycols; D000109:Acetylcholine; D009638:Norepinephrine