Encyclopedia of Pain

2013 Edition
| Editors: Gerald F. Gebhart, Robert F. Schmidt

Neurokinin

Reference work entry
DOI: https://doi.org/10.1007/978-3-642-28753-4_201403

Definition

The tachykinins are a family of small biologically active peptides whose principal mammalian members are substance P (11 amino acids) and neurokinin (NK) A and B (10 amino acids). These peptides are derived from precursor proteins, the preprotachykinins, which are encoded by two different genes. Three receptors for tachykinins, the so-called neurokinin receptors NK1, NK2, and NK3, have been cloned and characterized to have seven transmembrane spanning segments, to be coupled to G proteins and to be linked to the phosphoinositide signaling pathway. Although NK1 receptors are considered to be substance P-preferring, NK2 receptors NKA-preferring, and NK3 receptors NKB-preferring, substance P, NKA, and B are full agonists at all three tachykinin receptors.

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© Springer-Verlag Berlin Heidelberg 2013