Tachykinin GPCR Family Subtypes and Products

What Are Tachykinin Receptors?

Tachykinin receptors are a family of G protein-coupled receptors (GPCRs) comprised of three receptor subtypes: NK1, NK2, and NK3. While NK1 and NK3 receptors are found within the central nervous system, NK2 receptors are found within smooth gastrointestinal muscle and specific parts of the brain. Tachykinin receptor antagonists have therapeutic potential in the treatment of anxiety, depression, and schizophrenic disorders, although recent clinical studies have not proved successful. Aprepitant, an NK1 antagonist, has current application as an anti-nausea drug for chemotherapy treatment.

Tachykinin Receptor Information

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NK1

NK2

NK3

NK1 (or tachykinin receptor TACR1) is a selective receptor for substance P with relatively higher affinity for neurokinin A compared to neurokinin B (100- and 500-fold lower). Neurons in lamina I of the spinal dorsal horn express the NK1 receptor for substance P and mediate hyperalgesia, an enhanced sensitivity to painful stimuli. Although substance P does not mediate the signaling of acute pain or hyperalgesia, it is essential for the full development of stress-induced analgesia and for an aggressive response to territorial challenge. It is also suggested that substance P is important for orchestrating the response of the animal to major stressors such as pain, injury or invasion of territory. Modulation of substance P activity offers a radical new approach to the management of depression, anxiety and stress. The substance P receptor is highly expressed in areas of the brain that are implicated in these behaviors.

The tachykinin receptor 2 (TACR2 or NK2) is a receptor for the tachykinin family of peptide neurotransmitters. NK2 receptor selectively binds neurokinin A (substance K), which is predominating in human and animal airways. It has been shown to regulate circular muscle contraction. NK2 can be found in tracheal and gastric tissues.

Three membrane receptors that recognize these tachykinins have been described, termed TACR1, TACR2, and TACR3 (or NK3). Their endogenous ligands are substance P, neurokinin A, and neurokinin B, respectively. Interest in the tachykinins and their respective receptors has been stimulated by their potential role in bronchial asthma.

Tachykinin Cell Lines

Receptor FamilyReceptorSpeciesParentalStable Cell Lines Division-Arrested Cells Membranes
TachykininNK1humanHEK293TC1303DC1303MC1303
NK2humanHEK293TC1304DC1304MC1304
NK3humanHEK293TC1305DC1305MC1305
NK3ratHEK293TCr1305DCr1305MCr1305
NK3mouseHEK293TCm1305DCm1305MCm1305