SRS-A slow-reacting substance

SOZ Serum-opsonized zymosan SP Sulphapyridine SR Systemic reaction sr Sarcoplasmic reticulum SRBC Sheep red blood cells SRS Slow-reacting substance SRS-A Slow-reacting substance of anaphylaxis STZ Streptozotocin Sub P Substance P... 

At about the same time, a synthesis of leukotriene-A, also termed SRS-A ( slow reacting substance of anaphylaxis ), which made use of the Wittig olefmation was described77). The ylide of 100 is reacted with ethyl 5-formyl-2,4-pentadienoate 101 to give the ( , , Z, Z)- tetraenoic ester 102. Reduction and mesylation of 102, subsequent conversion into the sulfonium salt, and treatment of the latter with a base yields a sulfonium ylide which is reacted with methyl 4-formylbutanoate 69 to the epoxy-tetraenoic ester 103. After separation of the cis-epoxide by HPLC, 103 was treated with the S-trimethylsilyl derivative of glutathione dimethyl ester N-trifluoroacet-amide. The diastereomeric products thus obtained were separated by means of HPLC and hydrolyzed to 104 77) (Scheme 18). 

SRS-A slow-reacting substance of anaphylaxis (a mix of three leukotrienes). 

Concerning mediators of immediate hypersensitivity, the most important include histamine, leukotriene e.g., SRS-A (slow-reacting substance of anaphylaxis, ECF-A (eosinophil chemotactic factor of anaphylaxis), PAF (platelet-activating factor), and serotonin. There are also three classes of lipid mediators that are synthesized by activated mast cells through reactions initiated by the actions of phospholipase A2. These are prostaglandins, leukotrienes, and platelet-activating factors (PAF). 

In recent years, work on the biochemistry and chemistry of the leukotrienes has culminated in the characterization and chemical identification in 1979 of the constituents of SRS-A (slow reacting substance of anaphylaxis) " LTC4, LTD4,... 

Slow-reacting substance of anaphylaxis (SRS-A) is a mixture of leukotrienes C4, D4, and E4. This mixture of leukotrienes is a potent constrictor of the bronchial ait-way musculature. These leukotrienes together with leukotriene B4 also cause vascular permeabifity and attraction and activation of leukocytes and ate important regulators in many diseases involving inflammatory or... 

In the 1930s an unknown material was hypothesized that was proposed to cause a slow and sustained contraction of smooth muscle. It was named the slow reacting substance (SRS). By 1940 a similar substance was reported to be found in guinea pig lungs and was called the slow reacting substance of anaphylaxis (SRS-A). Over the next 40 years, while no one could isolate, characterize, or synthesize this mate-... 

SRS-A Lung tissue (Slow-reacting substance of anaphylaxis) Contraction of smooth muscle acidic polypeptide... 

LTC4 and LTD4 are potent bronchoconstrictors and are recognized as the primary components of the slow-reacting substance of anaphylaxis (SRS-A) that is secreted in asthma and anaphylaxis. There are four current approaches to antileukotriene drug development 5-LOX enzyme inhibitors, leukotriene-receptor antagonists, inhibitors of FLAP, and phospholipase A2 inhibitors. 

Eosinophils are attracted by proteins released by T cells, mast cells and basophils [eosinophil chemotactic factor of anaphylaxis (ECF-A)]. They bind schistosomulae coated with IgG or IgE, degranulate and release major basic protein, which is toxic. Eosinophils also release histaminase and aryl sulfatase, which inactivates histamine and Slow reacting substance of anaphylaxis (SRS-A). This results in antiinflammatory effects and inhibits migration of granulocytes to the site of injury. 

Corey, E.J., Albright, ).0., Burton, A.E. and Hashimoto, S. (1980) Chemical and enzymic syntheses of 5-HPETE, a key biological precursor of slow-reacting substance of anaphylaxis (SRS), and 5-HETE. Journal of the American Chemical Society, 102,1435-1436. 

Most cases of contact urticaria are of non-immunolo-gical origin, presumably due to the direct release of histamine, slow-reacting substance of anaphylaxis (SRS-A), bradykinin, or other vasoactive substances. Topical drugs and ingredients of cosmetics that have caused non-immunological contact urticaria are listed in Table 2. 

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