Demonstration of a neurokinin A receptor subtype in transfected fibroblasts

In competitive radioligand binding assays, the NK2 receptor antagonists [Tyr5,D-Trp6,8,9,Arg10]NKA(4-10) (MEN 10207) and [Tyr5,D-Trp6,8,9,Arg10]NKA(3-10) (MEN 10208) had high and low affinity, respectively, in bovine stomach membranes and SKLKB82#3 cells, a murine fibroblast cell line transfected with a cDNA encoding for the bovine NK2 receptor. These antagonists also had different affinities when inhibiting neurokinin A-induced polyphosphoinositide hydrolysis in SKLKB82#3 murine fibroblasts. Thus, the de novo protein expressed by the SKLKB82#3 murine fibroblasts may represent a distinct NK2 receptor subtype.