VI.5. Vasoconstrictors
A. Endothelins
These are paracrine vasoconstrictors produced by the endothelial cells:
The endothelins (ET1, ET2 and ET3) are structurally peptide molecules.
In the circulation, mainly ET1 is present.
This is currently the strongest known vasoconstrictor, but it has mainly a pathophysiological role.
It increases the production of prostacyclin, and salt and water reabsorption in the kidneys.
Their production is stimulated by:
epinephrine (catecholamine),
vasopressin,
cortisol,
oxidized LDL,
angiotensin,
hypoxia (lack of oxygen),
thrombin,
TNF-α,
the lack of shear stress,
the lack of basal dilatators (NO, PGE2 and PGI2) ,
Thromboxane A2 (TXA2),
PGF2α.
B. Effects of other molecules:
5-HT-indomethacin-sensitive contraction occurs in the large vessels.
OX causes endothelium-related vasodilatation.
Ethanol causes contraction in the brain vessels.
In summary, the endothelium plays a key role in the development of the MetS. The endothelium is very sensitive to age-related changes (more sensitive in childhood), and in adulthood it is sensitive to the lifestyle-related metabolic changes.