Slow-reacting substance of anaphylaxis
![](http://upload.wikimedia.org/wikipedia/commons/thumb/6/64/Leukotriene_C4.svg/200px-Leukotriene_C4.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d2/Leukotriene_D4.svg/200px-Leukotriene_D4.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Leukotriene_E4.svg/200px-Leukotriene_E4.svg.png)
The slow-reacting substance of anaphylaxis or SRS-A is a mixture of the leukotrienes LTC4, LTD4 and LTE4. Mast cells secrete it during the anaphylactic reaction, inducing inflammation.[1] It can be found in basophils.
It induces prolonged, slow contraction of smooth muscle and has a major bronchoconstrictor role in asthma.[2] Compared to histamine, it is approximately 1000 times more potent and has a slower onset but longer duration of action.[citation needed]
References
- ^ "Dorland's Medical Dictionary". Archived from the original on January 9, 2007. Retrieved December 15, 2006.
- ^ Howard R. Morris; Graham W. Taylor; Priscilla J. Piper; John R. Tippins (1980). "Structure of slow-reacting substance of anaphylaxis from guinea-pig lung". Nature. 285 (5760): 104–106. Bibcode:1980Natur.285..104M. doi:10.1038/285104a0. PMID 7374755. Retrieved December 15, 2006.
External links
- Slow+Reacting+Substance+of+Anaphylaxis at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
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Eicosanoids
- Arachidonic acid
Prostaglandins (PG) |
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Thromboxanes (TX) |
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Precursor | |
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Initial |
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SRS-A |
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Precursor |
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Eoxins |
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- Lipoxins (LX) (A4, B4)
- Virodhamine
- bronchoconstriction
- PGD2
- TXA2
- LTC4
- LTD4
- LTE4
- vasoconstriction
- PGF2α
- TXA2
- TXB2
- vasodilation
- PGE2
- PGI2
- LTC4
- LTD4
- LTE4
- platelets: induce
- TXA2
- inhibit
- PGD2
- PGI2
- leukocytes: induce
- TXA2
- LTB4
- inhibit
- PGD2
- PGE2
- fever stimulation:
- PGE2
- labor stimulation:
- PGE2 (Dinoprostone)
- PGF2α (Dinoprost)
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