Role of Endothelium in Regulation of the Brain Microcirculation

摘要

Endothelium is a major regulator of vascular tone. The primary mechanism by which endothelium regulates tone of underlying vascular muscle under normal conditions is by the release endothelium-derived relaxing factor(s) (EDRFs). These factors include nitric oxide, endothelium-derived hyperpolarizing factor(s) and prostacyclin [19, 69]. Although there are a few exceptions [see 19 and 20 for detailed reviews, 79], the vast majority of available evidence suggests that under normal conditions, nitric oxide is the predominant EDRF in both large arteries and microvessels of the cerebral circulation. For this reason, the present review will focus on the functional importance of endothelium-derived nitric oxide in regulation of cerebral vascular tone. In addition, mechanisms ofnltnc oxide mediated signaling, the interaction of nitric oxide and superoxide, and examples of changes in the functional importance of endothelium-derived nitric oxide in disease states will be summarized.