EVIDENCE FOR BRADYKININ B2-RECEPTORS ON CULTURED HUMAN DECIDUA CELLS

Bradykinin is known to be present at sites of acute inflammation and t o exert its potent inflammatory effects mainly via the bradykinin B2-r eceptor. Recently, bradykinin dependent processes have been described in cultured human decidual cells, so that bradykinin may expand the li st of paracrine factors involved in labour induction. In this paper we present the results of in vitro studies giving evidence that these ce lls carry the bradykinin B2-receptor. By immunocytochemical methods th e receptor protein was localized on decidual cells. Analysis of cellul ar extracts of cultured decidual cells by RT-PCR showed the presence o f the specific mRNA coding for the bradykinin B2-receptor. Binding stu dies revealed a single, saturable and specific binding site for bradyk inin of high affinity (K-d = 0.85 nM, B-max = 436 fmol/mg protein). Co mpetitive binding studies showed displacement of [H-3]-bradykinin by H OE 140, but not by the ligands for the bradykinin B1-receptor, des-Arg (10)-kallidin and [Leu(8)]-des-Arg(9)-bradykinin. The results are cons istent with the presence of the bradykinin B2-receptors.