We Although a bradykinin receptor cDNA has been isolated from rat uterine smooth muscle (22) and from human fibroblasts (23) METHODSCell Culture. PC12 cells were maintained in L15CO2 medium (30) containing 7% horse serum and 7% fetal bovine serum and supplemented with 16.7 mM glucose, penicillin (100 units/ml), streptomycin sulfate (100 pg/ml), fresh vitamin mix (30), and 2 mM glutamine. COS-1 cells (simian Abbreviations: IP2, inositol bisphosphate; IP3, inositol trisphosphate; Thi, f-(2-thienyl)alanine.