sentences:  In the mid 1980s, the additional mammalian tachykinin neurokinin A (NKA) and neurokinin B (NKB) were discovered.This led to further research, resulting in the isolation of the genes that encoded the mammalian tachykinins and eventually the discovery of three different tachykinin receptors.In 1984, it was decided that the tachykinin receptors should be called tachykinin NK1 receptor, tachykinin NK2 receptor and tachykinin NK3 receptor.