Neurokinin A (4-10) is a tachykinin NK2 receptor agonist. NK2 receptor[1]
Neurokinin A (NKA) and its truncated form NKA(4-10) are potent spasmogens of human colon circular muscle, an action mediated exclusively via tachykinin NK2 receptors. A structure-activity study of the neurokinin A (NKA) fragment NKA(4-10) is performed to investigate the importance of amino acid residues for receptor efficacy, potency and affinity at the NK2 receptor in human colon circular muscle. A high density of NK2 receptors has been demonstrated in this tissue, using in vitro autoradiography and radioligand binding[1].
[1]. Warner FJ, et al. Structure-activity relationship of neurokinin A(4-10) at the human tachykinin NK(2) receptor: the effect of amino acid substitutions on receptor affinity and function. Biochem Pharmacol. 2002 Jun 15;63(12):2181-6.