Neurokinin A(4-10) TFA

NK ₂ receptor

Neurokinin A (NKA) and its truncated form NKA(4-10) are potent spasmogens of human colon circular muscle, an action mediated exclusively via tachykinin NK ₂ 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 NK ₂ receptor in human colon circular muscle. A high density of NK ₂ receptors has been demonstrated in this tissue, using in vitro autoradiography and radioligand binding.