Endothelium-derived hyperpolarizing factor.
Although nitric oxide appears to be the major endothelium-derived relaxing factor (EDRF), it cannot explain all endothelium-dependent responses of isolated arteries. Thus, acetylcholine causes an endothelium-dependent, transient hyperpolarization, which is due to the release from the endothelial cells of a diffusible substance (endothelium-derived hyperpolarizing factor, EDHF) other than nitric oxide. The muscarinic receptors on the endothelium that trigger the release of EDHF belong to the M1-muscarinic subtype, while those activating the liberation of EDRF are M2-muscarinic in nature. The importance of endothelium-dependent hyperpolarization varies among different blood vessels. The hyperpolarization, and the resulting relaxation caused by EDHF can be attributed to an increase in K+ conductance in the vascular smooth muscle. Although the nature of EDHF remains elusive, it may be a labile metabolic of arachidonic acid.
Komori
K
K
Department of Physiology and Biophysics, Mayo Clinic, Rochester, Minn.
Vanhoutte
P M
PM
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000378:metabolism*; D004563:Electrochemistry; D009129:Muscle Tonus; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology
D009569:Nitric Oxide; D000109:Acetylcholine