Event: 937

Key Event Title


KE7 : Impaired, Vasodilation

Short name


Impaired, Vasodilation

Biological Context


Level of Biological Organization

Organ term


Organ term
circulatory system

Key Event Components


Process Object Action
vasodilation blood vessel abnormal

Key Event Overview

AOPs Including This Key Event


AOP Name Role of event in AOP
Hypertension KeyEvent



Taxonomic Applicability


Term Scientific Term Evidence Link
Homo sapiens Homo sapiens High NCBI
Oryctolagus cuniculus Oryctolagus cuniculus Low NCBI
Mus musculus Mus musculus Moderate NCBI
Rattus norvegicus Rattus norvegicus Moderate NCBI

Life Stages


Life stage Evidence
All life stages High

Sex Applicability


Term Evidence
Unspecific High

Key Event Description


Vasodilation refers to the widening or increase in the diameter of blood vessels (e.g. large arteries, large veins, small arterioles) that is caused by the relaxation of vascular smooth muscle cells (VSMCs) within the walls of blood vessels, thus increasing blood flow and decreasing arterial blood pressure and heart rate (Siddiqui, 2011). VSMC relaxation is regulated through a number of mechanisms, including cyclic GMP-dependent hyperpolarization and relaxation via nitric oxide (NO), cAMP-dependent hyperpolarization via prostaglandins, and stimulation of potassium channels via endothelial-derived hyperpolarizing factors (Durand and Gutterman, 2013). Under oxidative stress, decreased NO bioavailability results in impaired vasodilation, which is associated with cardiovascular diseases such as hypertension (Silva et al., 2012).

How It Is Measured or Detected


Endothelium-dependent vasodilation can be measured using invasive and non-invasive methods (Raitakari and Celermajer, 2000). For the invasive approach, vasodilation is measured after intra-arterial pharmacologic stimulation with substances that enhance NO release (e.g. acetylcholine, bradykinin). The non-invasive ultrasound-based method evaluates flow-mediated vasodilation (FMD) in the superficial arteries, such as brachial, radial, or femoral vessels.

Guidelines for the measurement of FMD have been published (Corretti et al. 2002).

Domain of Applicability


Vasodilation has been observed in humans, rabbits, mice and rats.



Guidelines for the ultrasound assessment of endothelial-dependent flow-mediated vasodilation of the brachial artery

Corretti MC, Anderson TJ, Benjamin EJ, Celermajer D, Charbonneau F, Creager MA, Deanfield J, Drexler H, Gerhard-Herman M, Herrington D, Vallance P, Vita J, Vogel R.  Guidelines for the ultrasound assessment of endothelial-dependent flow-mediated vasodilation of the brachial artery.  Journal of the American College of Cardiology, 2002, 39 (2) 257-265

Durand, M.J., and Gutterman, D.D. (2013). Diversity in mechanisms of endothelium-dependent vasodilation in health and disease. Microcirc. N. Y. N 1994 20, 239–247.

Raitakari, O.T., and Celermajer, D.S. (2000). Flow-mediated dilatation. Br. J. Clin. Pharmacol. 50, 397–404.

Siddiqui, A. (2011). Effects of Vasodilation and Arterial Resistance on Cardiac Output. J. Clin. Exp. Cardiol. 02.

Silva, B.R., Pernomian, L., and Bendhack, L.M. (2012). Contribution of oxidative stress to endothelial dysfunction in hypertension. Front. Physiol. 3, 441.