Endothelium-derived relaxing factor in brain blood vessels is not nitric oxide

Abstract

Background: The endothelium-derived relaxing factor that mediates the actions of acetylcholine is now most frequently identified as nitric oxide. Nitric oxide is believed to have numerous important regulating actions in neurons, blood vessels, and several other biological systems. Summary of Review: The literature concerning tissue other than cerebral blood vessels supports the conclusion that the endothelium-derived relaxing factor for acetylcholine is either nitric oxide or a compound formed from and containing nitric oxide Conclusions: In brain blood vessels the chemical identity of the endothelium-derived relaxing factor mediating the action of acetylcholine is unknown, but this relaxing factor does not appear to be nitric oxide. If the mediator contains nitric oxide, as is probably the case, the means by which it activates vascular guanylate cyclase and/or produces dilation is unknown. Since this relaxing factor inhibits platelet adhesion/aggregation in cerebral vessels as well as relaxing these vessels, the chemical identification of this relaxing factor and the elucidation of its mode of action are extremely important to our understanding and control of cerebrovascular phenomena in health and disease. © 1992 American Heart Association, Inc.