Endothelium-dependent relaxations and chronic vasospasm after subarachnoid hemorrhage.

Endothelium-dependent relaxations are abolished in the canine basilar artery after subarachnoid hemorrhage. However, the release of endothelium-derived relaxing factor (EDRF) toward the lumen is not reduced. These findings suggest that the responsiveness of the smooth muscle to EDRF is impaired during chronic vasospasm after subarachnoid hemorrhage.