Substance P

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Substance P
Substance P
Properties of human protein
Mass / length primary structure 11 AS ; 1348  there
Precursor Protachykinin-1 (110 AA; 12910 Da)
Gene name TAC1
External IDs

Substance P is a neuropeptide made up of eleven amino acids (primary structure: Arg − Pro − Lys − Pro − Gln − Gln − Phe − Phe − Gly − Leu − Met − NH 2 ). It belongs to the group of neurokinins (formerly also known as tachykinins ) and is formed by nerve cells , but also by leukocytes . The letter P originally stood for Engl. powder , because the substance was in the form of a powder, today the P is interpreted as pain .

Substance P was initially regarded as a neurotransmitter for pain receptors ( nociceptor ) and pain-conducting C-fibers . If such a receptor is more strongly excited, it releases substance P. But it also plays a role as a modulator in inflammation . In local inflammation, it is formed by the afferent neurons of the spinal nerves and in projection paths of the spinal cord tract.

Substance P causes a strong expansion of the blood vessels and increases the permeability of the vessel wall. In addition, it increases the sensitivity of the pain neurons in the spinal cord. Substance P also regulates the targeted immigration of leukocytes ( chemotaxis ). Leukocytes express both substance P and the substance P receptor (neurokinin-1 receptor, NK-1R).

Substance P antagonists are currently the focus of scientific research, e.g. B. for pain therapy and as an antidepressant . An excess of substance P is discussed as a possible cause of fibromyalgia . In addition, substance P can induce vomiting by activating the neurokinin receptors. A corresponding antagonist that is used to prevent acute and delayed nausea and vomiting is aprepitant .

Capsaicin , a substance from paprika (especially chillies, the hot representatives of paprika), activates the heat receptors in the oral mucosa, which leads to the release of substance P into the tissue and pain-like sensations. With regular use of capsaicin, the body gets used to it and the amount of substance P released becomes less. This is explained by an increased release of endogenous opioids, the endorphins and enkephalins .

In mammals , substance P is absent in the naked mole rat , which therefore presumably shows a certain resistance to pain.

Substance P is probably a "key responder" when exposed to most stressors - with the aim of ensuring the organism's homeostasis. That is why substance P is also characterized as a regulatory peptide.

Extensive studies exist on the interaction of substance P with the aminergic system of the adrenal medulla. In this way, substance P could contribute to coping with stressful situations by securing homeostasis of the aminergic system.

Web links

  • Kampik, K. (2005): The influence of substance P on sleep in healthy people. Dissertation, Freiburg i. Br. PDF; 1.6 MB

Individual evidence

  1. UniProt P20366
  2. ^ Hecht, K. , P. Oehme and M. Poppei: Action of Substance P on neurotic-hypertensive rats. In: Pharmazie , 34, 654-657, 1979.
  3. Oehme, P. , K. Hecht , L. Piesche, H. Hilse, E. Morgenstern and M. Poppei: Substance P as a modulator of physiological and pathological processes. In: Marsan, CA, WZ Traczyk and US v. Euler (Ed.): Neuropeptides and neural transmission. In: International brain organization monograph series 7, pp. 73-84, Raven Press, New York 1980.
  4. ^ Oehme, P. and WA Krivoy: Substance P - a peptide with unusual features. In: Trend in Pharmacological Sciences , 4, pp. 521-523, 1983.
  5. ^ Cheung, NS, P. Karlsson. JX. Wang, M. Bienert, P. Oehme and BC Livett: Functional studies with Substance P analogues: effects of N-terminal, C-terminal and C-terminus-extended analogues of Substance P on nicotine-induced secretion and desensitization in cultured bovine adrenal chromaffine cells. In: J. Neurochemistry 62, pp. 2246-2253, 1994.
  6. Peter Oehme , Karl Hecht : Reflections on substance P research; Reflections on Substance P Research (with 50 references). Leibniz Society of Sciences in Berlin, 2017.