Related Experiment Videos
Relationship between extraluminal oxyhemoglobin and endothelium-dependent vasodilatation in isolated perfused canine
1Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan.
Abstract:
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.