NK2R

Neurokinin receptor NK2R, encoded by TACR2, is a tachykinin G protein-coupled receptor cloned from human tracheal and gastric tissues and primarily activated by neurokinin A^[1]. Mechanistically, NK2R signaling supports smooth muscle contractility, epithelial secretion, inflammation, and nociception within gastrointestinal, respiratory, urogenital, immune, and nervous systems^[2]. In human colon models, NK2 tachykinin receptors play a dominant role in circular muscle contraction and modulate motor responses in colonic muscle strips^[3][4]. In airway models, NK2 receptors mediate airway smooth muscle contraction, especially in human bronchi, and contribute to antigen- or PAF-associated bronchospasm and airway hyperresponsiveness^[5][6]. Compared with related isoforms, NK1R preferentially responds to substance P, NK2R to neurokinin A, and NK3R to neurokinin B, which supports isoform-specific ligand selection in receptor studies^[2]. For experimental applications, NK2R antagonists such as MEN10,627 and nepadutant provide selective tools for testing NK2R-dependent gastrointestinal motility and bronchoconstriction mechanisms^[6][7].