Displacement of125I-Tyr3-NT bound to membranes prepared from NTRL cDNA-transfected COS-7 cells by NT, levocabastine,d-Trp11-NT, SR48692, and NT (1–10). Experimental details are described in Materials and Methods. The binding of 125I-Tyr3-NT was measured in the presence of increasing concentrations of NT (closed circles), levocabastine (open circles),d-Trp11-NT (closed triangles), SR48692, (open squares), and NT (1–10) (open triangles). Each point represents the mean of two separate experiments.