WIN-64821 is a secondary metabolite produced by Aspergillus species, and acts as a Neurokinin Receptor antagonist. The Ki values of WIN-64821 for NK1, NK2 and NK3 receptors are 0.24 (human astrocytoma cells), 0.26 (rat duodenum) and 15.2 (guinea pig forebrain) µM, respectively. WIN-64821 inhibits apamin-induced contraction of rat vas deferens, blocks substance P-induced contraction of guinea pig ileum and Ca2+ efflux in human astrocytoma cells. WIN-64821 is applicable to analgesic and anti-inflammatory research[1][2].