title: Endothelium-dependent relaxation of canine basilar arteries. Part 2: Inhibition by hemoglobin and cerebrospinal fluid from patients with aneurysmal subarachnoid hemorrhage.
abstract: The effects of hemoglobin and cerebrospinal fluid from patients with subarachnoid hemorrhage (CSF-SAH) on endothelium-dependent relaxation were studied. At 10(-6) M, hemoglobin somewhat inhibited the endothelium-dependent relaxation induced by A23187 in rings of canine basilar artery. At 3 X 10(-6) M, it almost completely inhibited the same response. At 3 X 10(-6) M, hemoglobin did not significantly inhibit smooth muscle relaxation mechanisms as papaverine-induced relaxation was not inhibited by hemoglobin. It was also demonstrated that pretreatment of arterial rings with CSF-SAH resulted in a dose-dependent inhibition of relaxation induced by A23187. The inhibitory effect of CSF-SAH was prominent in the case in which a high oxyhemoglobin concentration was measured by spectrophotometry. Normal CSF from patients without SAH did not affect endothelium-dependent relaxation. These results suggest that hemoglobin released from lysed erythrocytes inhibits endothelium-dependent relaxation of canine basilar arteries and may also play an important role in the pathogenesis of cerebral vasospasm after aneurysmal subarachnoid hemorrhage.
mesh_terms: D000818:Animals; D001488:Basilar Artery / Q000032:analysis*; D000001:Calcimycin / Q000494:pharmacology; D004285:Dogs; D004727:Endothelium / Q000502:physiology*; D005260:Female; D006454:Hemoglobins; D006801:Humans; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D009569:Nitric Oxide; D013345:Subarachnoid Hemorrhage / Q000134:cerebrospinal fluid*; D014664:Vasodilation; D014665:Vasodilator Agents / Q000302:isolation & purification*
chemical_list: D006454:Hemoglobins; D014665:Vasodilator Agents; D009569:Nitric Oxide; D000001:Calcimycin