Abstract
The present study was designed to assess a role of hemoglobin in the genesis of vasospasms following subarachnoid hemorrhages. Isolation of human hemoglobin A0 was carried out by chromatography using DEAE-Sephadex A50. The in vitro contractile activities of human hemoglobin were analyzed quantitatively in isolated dog arterial segments. The following results were obtained.
1) Human hemoglobin Aa caused dose-related contractions in the basilar arteries. The dose-response curve of hemoglobin A0 was obtained.
2) The dose-response curve of hemoglobin A0 was almost identical with that of red blood cell hemolysates. This result indicates that hemoglobin is mainly responsible for contractile activities of red blood cell hemolysates.
3) The maximum contraction induced by hemoglobin A0 was 70% of that induced by serotonin.
4) The sensitivity of the basilar arteries to hemoglobin was markedly greater than that of the peripheral arteries.
5) Oxyhemoglobin caused greater contraction in the basilar arteries than methemoglobin.
6) Globin, protoporphyrin, hematin, ferrous chloride and ferric chloride did not cause significant contractions in the basilar arteries.
These data suggest that hemoglobin plays an important role in the genesis of vasospasms following rupture of an aneurysm.
