Endothelium-dependent hyperpolarization: a role in the control of vascular tone.
Endothelial-dependent relaxation of vascular smooth muscle cells evoked by a number of agonists, including cholinomimetics and substance P, is often accompanied by an increase (repolarization and/or hyperpolarization) in the membrane potential. This change in membrane potential appears predominantly to reflect the action of an endothelial-derived hyperpolarizing factor (EDHF), which is distinct from NO (or endothelial-derived relaxing factor), and is discussed in this article by Chris Garland and colleagues. In large conducting arteries, EDHF may provide a secondary system to NO, which assumes primary importance in some disease states such as pulmonary hypertension and atherosclerosis. However, in small resistance arteries (100-300 microns), EDHF appears to be a major determinant of vascular calibre under normal conditions, and may therefore be of primary importance in the regulation of vascular resistance.
Garland
C J
CJ
Department of Pharmacology, University of Bristol, UK.
Plane
F
F
Kemp
B K
BK
Cocks
T M
TM
D000818:Animals; D001685:Biological Factors / Q000032:analysis / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D009129:Muscle Tonus / Q000502:physiology*
D001685:Biological Factors; C067410:endothelium-dependent hyperpolarization factor