[Frontiers in Bioscience S3, 730-744, January 1, 2011]

The endothelium in compliance and resistance vessels

Chris R Triggle, Hong Ding

Departments of Medical Education and Pharmacology, Weill Cornell Medical College in Qatar, P.O. Box 24144, Education City, Doha, Qatar


1. Abstract
2. Introduction
3. Endothelium-dependent regulation of blood vessels.
4. Endothelium-Dependent Hyperpolarization (EDH).
4.1. What is endothelium-derived hyperpolarizing factor (EDHF)?
5. Is there an anatomical and/or physiological basis for the absence of an apparent significant contribution of EDHF in conduit vessels?
5.1. Importance of myoendothelial gap junction (MEGJs) in the regulation of vascular tone
5.2. The role of microdomains
6. Calcium signalling and endothelium-dependent vasodilatation (EDV)
6.1. Role of calcium sensing receptors (CaSR) in the regulation of endothelial cell function
6.2. Calcium signalling and endothelial cell microdomains
7. Disease progression
7.1. Endothelial nitric oxide synthase (eNOS) and endothelial dysfunction
7.2. EDHF and endothelial dysfunction
7.3. Endothelium-derived contracting factors (EDCFs) and vascular disease
8. Summary
9. Acknowledgements
10. References


The endothelium is a single layer of cells lining all blood vessels. Although the endothelium is not an organ it does, nonetheless have autocrine, paracrine and endocrine-like functions that affect the cardiovascular system. Until the description in 1980 by Nobel Laureate Robert Furchgott of endothelium-derived relaxing factor (EDRF), later identified as nitric oxide (NO), the endothelium was considered to be a semi-permeable barrier between the blood and the smooth muscle cell layers of the blood vessel. Heterogeneity exists in the functions of the endothelium with differences evident between species and between the large conduit compliance vessels and the resistance vessels of the microcirculation. Endothelial dysfunction, defined as a reduction in the ability of the endothelium to transmit a vasodilatation influence on blood flow, has prognostic significance and serves as an early indicator of the development of vascular disease as well as a therapeutic target. This review compares the role of the endothelium in the regulation of vascular tone in conduit versus resistance vessels and how alterations in endothelial function may lead to vascular disease.