Relationship between extraluminal oxyhemoglobin and endothelium-dependent vasodilatation in isolated perfused canine internal carotid arteries.
The stainless steel cannula insertion method was applied to investigate the endothelium-dependent relaxation of canine intracranial internal carotid arteries. The arteries were precontracted by extraluminally administrated 0.67 X 10(-4) M 5-hydroxytryptamine or 10(-5) M oxyhemoglobin (oxyHb). There was no significant difference between these groups in the dose-response curves of acetylcholine (ACh)-induced relaxation. The concentration of oxyHb used was enough to abolish the endothelium-dependent relaxation by ACh when administered intraluminally in this preparation. The blocking effect of oxyHb to endothelium-derived relaxing factor (EDRF) did not appear for at least 3 hours after the extraluminal application of 10(-5) M oxyHb. These results suggest that the inactivation of EDRF by oxyHb may not play an important role in producing cerebral vasospasm in the initial stage after subarachnoid hemorrhage.
Tanaka
Y
Y
Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan.
Chiba
S
S
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002339:Carotid Arteries / Q000187:drug effects / Q000502:physiology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D010108:Oxyhemoglobins / Q000494:pharmacology*; D010477:Perfusion; D012701:Serotonin / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D010108:Oxyhemoglobins; D012701:Serotonin; D000109:Acetylcholine