Substance P
From Wikipedia, the free encyclopedia
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| Spacefilling model of substance P | |
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tachykinin, precursor 1
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| Identifiers | |
| Symbol | TAC1 |
| Alt. Symbols | TAC2, NKNA |
| Entrez | 6863 |
| HUGO | 11517 |
| OMIM | 162320 |
| RefSeq | NM_003182 |
| UniProt | P20366 |
| Other data | |
| Locus | Chr. 7 q21-q22 |
| Substance P | |
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| Identifiers | |
| CAS number | [33507-63-0] |
| PubChem | |
| MeSH | |
| Properties | |
| Molecular formula | C63H98N18O13S |
| Molar mass | 1347.63 g/mol |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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In neuroscience, Substance P is a neuropeptide: a short-chain polypeptide that functions as a neurotransmitter and as a neuromodulator. It belongs to the tachykinin neuropeptide family.
It is an 11-amino acid polypeptide with the sequence: Arg Pro Lys Pro Gln Gln Phe Phe Gly Leu Met
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[edit] History
It was discovered by Ulf von Euler and John H. Gaddum in 1931.
[edit] Receptor
The endogenous receptor for Substance P is neurokinin 1 receptor (NK1-receptor, NK1R). It belongs to the tachykinin receptor sub-family of GPCRs.
[edit] Functions
In the central nervous system, substance P has been associated in the regulation of mood disorders, anxiety, stress, reinforcement, neurogenesis, respiratory rhythm, neurotoxicity, nausea/emesis, pain and nociception.
[edit] Vomiting
The vomiting center in the brainstem contains high concentrations of substance P and its receptor, in addition to other neurotransmitters such as choline, histamine, dopamine, serotonin, and opioids. Their activation stimulates the vomiting reflex. Different emetic pathways exist, and substance P/NK1R appears to be within the final common pathway to regulate vomiting. [1]
Substance P antagonist (SPA) aprepitant is available in the market in the treatment of chemotherapy-induced nausea / emesis.
[edit] Pain
Substance P is involved in nociception, transmitting information about tissue damage from peripheral receptors to the central nervous system to be converted to the sensation of pain. It has been theorized that it plays a part in fibromyalgia. Capsaicin has been shown to reduce the levels of Substance P probably by reducing the number of C-fibre nerves or causing these nerves to be more tolerant. Thus Capsaicin is clinically used as an analgesic and anti-inflammatory agent to relieve pain associated with arthritis and many types of neuralgia.
[edit] Stimulating cellular growth
Substance P has been shown to stimulate cellular growth in cell culture [2], and it was shown that Substance P could promote wound healing of non-healing ulcers in humans. [3] It has also been shown to reverse diabetes in mice. [4]
[edit] Vasodilation
It also has effects as a potent vasodilator. This is caused by the release of nitric oxide from the endothelium. Its release can cause hypotension.
[edit] Eczema
High levels of BDNF and Substance P have been found associated with increased itching in eczema[5].
[edit] Substance P in gastrointestinal infection
Entamoeba histolytica is a single-celled parasitic protozoan that infects the lower gastrointestinal tract of humans, producing symptoms of diarrhea, constipation, and abdominal pain.[6][7] This protozoan was found to secrete serotonin[8], as well as substance P and neurotensin.[9]
[edit] Animals without Substance P
Naked mole rats lack Substance P and do not feel pain when painful stimuli are administered to the skin.[10][11]
[edit] References
- ^ Hornby PJ. Central neurocircuitry associated with emesis. Am J Med 2001;111:106S-12S
- ^ Reid TW, Murphy C, Iwahashi C, Foster B, and Mannis M. Stimulation of epithelial cell growth by the neuropeptide substance P. J Cell Biochem 1993; 52:476-485
- ^ Brown S, Lamberts D, Reid TW, Nishida T, Murphy C. Neurophilic and Anhidrotric Keratopathy Treated with Substance P and Insulinlike Growth Factor 1. Arch Ophthalmol 1997; 115:926-927
- ^ Breakthrough sheds light on cause of diabetes - health - 15 December 2006 - New Scientist. Retrieved on 2007-05-08.
- ^ 'Blood chemicals link' to eczema [1]
- ^ Steinitz H (1979). "[Chronic recurrent intestinal amebiasis in Israel (author's transl)]" (in German). Leber, Magen, Darm 9 (4): 175-9. PMID 491812.
- ^ Stark D, van Hal S, Marriott D, Ellis J, Harkness J (2007). "Irritable bowel syndrome: a review on the role of intestinal protozoa and the importance of their detection and diagnosis". Int. J. Parasitol. 37 (1): 11-20. doi:. PMID 17070814.
- ^ McGowan K, Kane A, Asarkof N, et al (1983). "Entamoeba histolytica causes intestinal secretion: role of serotonin". Science 221 (4612): 762-4. doi:. PMID 6308760.
- ^ McGowan K, Guerina V, Wicks J, Donowitz M (1985). "Secretory hormones of Entamoeba histolytica". Ciba Found. Symp. 112: 139-54. PMID 2861068.
- ^ Park TJ, Comer C, Carol A, Lu Y, Hong HS, Rice FL (2003). "Somatosensory organization and behavior in naked mole-rats: II. Peripheral structures, innervation, and selective lack of neuropeptides associated with thermoregulation and pain". J Comp Neurol 465 (1): 104–20. doi:. PMID 12926019.
- ^ Pepling, Rachel Sheremeta (January 7, 2004). Ugly Ducklings. Chemical & Engineering News. Retrieved on 2007-08-14.
[edit] External links
- http://www.fibromyalgiasupport.com/library/showarticle.cfm/id/3097 Dr. Jon Russell, M.D., Ph.D., Substance P is Key to Understanding Pain Process
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