Bradykinin stimulates production of inositol (1,4,5) trisphosphate in cultured mesangial cells of the rat via a BK2-kinin receptor.
1. Using [125I-Tyr0]-BK, as radiolabelled ligand, and various agonists and antagonists of bradykinin (BK) we identified a single class of specific BK2-binding sites in mesangial cell membranes (Bmax = 73 fmol mg-1 protein and Kd = 3.7 nM). 2. Following the addition of 0.1 microM BK, inositol (1,4,5) trisphosphate (IP3) formation increased within 20 s from a basal level of 64 to a maximal value of 175 pmol mg-1 protein. 3. Incubation in a Ca(2+)-free medium did not change IP3 production but a 5 min preincubation with 1 mM EGTA completely prevented the BK-induced IP3 formation, suggesting that IP3 formation is partly dependent on extracellular calcium. 4. The BK2 antagonist D-Arg-Hyp3-D-Phe7-BK (10 microM) but not the BK1 antagonist (des-Arg9-Leu8-BK) abolished IP3 production in response to 0.1 microM BK. Pretreatment of mesangial cells with pertussis toxin was without effect on BK-induced IP3 formation, whereas phorbol 12-myristate 13-acetate significantly enhanced (by 25%) BK-induced IP3 formation. 5. The present data demonstrate that inositol phosphate breakdown in rat mesangial cells can be mediated via activation of a BK2-kinin receptor and is under negative control of protein-kinase C.
Bascands
J L
JL
INSERM U133, Faculté Medecine, Toulouse, France.
Emond
C
C
Pecher
C
C
Regoli
D
D
Girolami
J P
JP
D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000031:analogs & derivatives / Q000494:pharmacology*; D002478:Cells, Cultured; D005920:Glomerular Mesangium / Q000187:drug effects / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis*; D007457:Iodine Radioisotopes; D007700:Kinetics; D037342:Pertussis Toxin; D051381:Rats; D011919:Rats, Inbred Strains; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000700:Analgesics; D007457:Iodine Radioisotopes; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter; D010566:Virulence Factors, Bordetella; D015544:Inositol 1,4,5-Trisphosphate; C053010:NPC 567; D037342:Pertussis Toxin; D013755:Tetradecanoylphorbol Acetate; D001920:Bradykinin