Autacoids are biological factors that are primarily characterized by the effect they have upon smooth muscle. With respect to vascular smooth muscle, there are both vasoconstrictor and vasodilator autacoids. Cultured Smooth muscle of the aorta. ... Vascular smooth muscle refers to the particular type of smooth muscle found within, and composing the majority of the wall of blood vessels. ... Vasoconstriction is the constriction of blood vessels, in other words, when the lumen narrows. ... Vasodilation is where blood vessels in the body become wider following the relaxation of the smooth muscle in the vessel wall. ...

Vasodilator autacoids can be released during periods of exercise. Their main effect is seen in the skin, allowing for heat loss.

The word Autacoids comes from the Greek "Autos" (self) and "Acos" (drug). These are local hormones, therefore have a paracrine effect. Some notable autacoids are: eicosanoids, angiotensin, neurotensin, NO (nitric oxide), kinins, histamine, serotonin, endothelins, etc. Paracrine signalling is a form of signalling in which the target cell is close to the signal releasing cell, and the signal chemical is broken down too quickly to be carried to other parts of the body. ... In biochemistry, eicosanoids are a class of oxygenated hydrophobic molecules that largely function as autocrine and paracrine mediators. ... Angiotensin is an oligopeptide in the blood that causes vasoconstriction, increased blood pressure, and release of aldosterone from the adrenal cortex. ... Neurotensin is a 13 amino acid neuropeptide that is implicated in the regulation of luteinizing hormone and prolactin release and has significant interaction with the dopaminergic system. ... R-phrases , , , , S-phrases , , , Supplementary data page Structure and properties n, εr, etc. ... A kinin is any of various structurally related polypeptides, such as bradykinin and kallikrein, that act locally to induce vasodilation and contraction of smooth muscle. ... This article or section does not cite any references or sources. ... Serotonin (5-hydroxytryptamine, or 5-HT) is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system (CNS) and enterochromaffin cells in the gastrointestinal tract of animals including humans. ... Endothelin is a 21-amino acid vasoconstricting peptide that plays a key part in vascular homeostasis. ...

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• MeSH Autacoids