Mass measurements of inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate in a neuronal cell line stimulated with bradykinin: inositolphosphate response shows desensitization.
In a neuronal cell line (108CC15, NG108-15) the levels of inositol 1,4,5-trisphosphate (InsP3) and inositol 1,3,4,5-tetrakisphosphate (InsP4), as measured by receptor binding assays, rise transiently after stimulation with bradykinin (EC50 approx. 150 nM). Maximal InsP3 level of 354 pmol/mg protein (15-fold basal level) is obtained at 10-15 s after addition of bradykinin, the InsP4 level rises maximally to 78 pmol/mg protein (14-fold basal level) at 20-30 s. In a rat glioma cell line, bradykinin (2 microM) causes a fast 6-fold increase in InsP3 and InsP4 levels. In the neuronal cells the bradykinin-dependent rise of the inositolphosphate levels is diminished with reduced extracellular Ca2+ concentration. However, depletion of internal Ca2+ stores does not affect the bradykinin-induced rise in InsP3 and InsP4 levels. Homologous desensitization to bradykinin occurs in the signal transduction pathway already at the production of inositolphosphates, since after a 2 min stimulation with bradykinin the rise in cellular masses of InsP3 and InsP4, inducible by a following second bradykinin stimulus, is substantially reduced.
Donié
F
F
Physiologisch-chemisches Institut, Universität Tübingen, Germany.
Reiser
G
G
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D002460:Cell Line; D005910:Glioma; D006822:Hybrid Cells / Q000187:drug effects / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D007295:Inositol Phosphates / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D009447:Neuroblastoma
D007295:Inositol Phosphates; C081655:inositol-1,3,4,5-tetrakisphosphate; D015544:Inositol 1,4,5-Trisphosphate; D001920:Bradykinin; D002118:Calcium