Inflammatory response eicosanoids

In addition to participating in the inflammatory response, eicosanoids also regulate smooth muscle contraction (particularly in the intestine and uterus). They increase water and sodium excretion by the kidney and are involved in regulating blood pressure. They frequently serve as modulators some eicosanoids stimulate and others inhibit the same process. For example, some serve as constrictors and others as dilators of blood vessels. They are also involved in regulating bronchoconstriction and bronchodilation... 

Inflammation is the normal host response to infection or injury that mediates immune elimination of pathogens and tissue repair. Inflammatory processes include increased production of cytokines, chemokines, nitric oxide, and eicosanoids by the innate immune system in conjunction with altered leukocyte homing, all of which greatly impact acquired immunity. Aberrant inflammatory responses evoke both acute injury such... 

Like nitric oxide, the discovery of the eicosanoid signalling molecules was a significant event in twentieth century physiology, due largely to research led by Sir John Vane (Nobel Prize 1982). The diverse actions of the eicosanoids include roles in muscle contraction, blood coagulation, salt and fluid homeostasis, inflammatory responses and pain sensitivity. 

The eicosanoids have a broad spectrum of physiological activities and these are elicited at very low concentrations, 10 M or less. They mediate the inflammatory response, produce pain and fever, regulate blood pressure, initiate blood clotting, induce labor, and regulate the sleep/wake cycle. 

In rheumatoid arthritis, immune complexes are deposited in the affected joints, causing an inflammatory response that is amplified by eicosanoids. Lymphocytes and macrophages accumulate in the synovium, whereas leukocytes localize mainly in the synovial fluid. The major eicosanoids produced by leukocytes are leukotrienes, which facilitate T-cell proliferation and act as chemoattractants. Human macrophages synthesize the COX products PGE2 and TXA2 and large amounts of leukotrienes. 

In addition to bioactive eicosanoids, the inflammatory response involves the sequential activation of various signaling pathways, including reactive oxygen intermediates, cytokines, growth factors, enzymes,... 

Elsewhere, the effects of propolis and its components on eicosanoid production during the inflammatory response have been investigated. This investigation demonstrates that both propolis and its component, chlorogenic acids, inhibit eicosanoid production which can strongly affect the immune and inflammatory response. Consequently, the effect on eicosanoid production by propolis may be due to chlorogenic acids of propolis component [83],... 

Leukotriene One of the 20-carbon fatty acid compounds (eicosanoids) formed from arachidonic acid by the lipoxygenase enzyme. Leukotrienes are important in mediating certain allergic and inflammatory responses, especially in respiratory tissues. 

Activated leukocytes at a site of inflammation release compounds which enhance the inflammatory response. The account below focuses on cytokines and eicosanoids (arachidonic acid metabolites) becaiase of their therapeutic implications. Nevertheless, the complexity of the response, and its involvement of other systems, is indicated by the range of mediators, which include ... 

A critical aspect of the inflammatory response is the ability to stop the inflammation, referred to as the resolution phase, an active process involving expression of anti-inflammatory agents. Activation of PLA2S release ArAc, eicosapentae-noic acid, and DHA. ArAc is metabolized to eicosanoids (prostaglandins,... 

---