Bradykinin inhibition of N- and L-type calcium channel currents in NG108-15 cells

The bradykinin regulation of calcium channel currents in NG108-15 neuroblastoma x glioma hybrid cells was examined, in order to determine: (1) which type of bradykinin receptor mediates the inhibition of N-type calcium channels in these cells; and (2) whether bradykinin can modulate other types of calcium channels in these cells. Bradykinin inhibited both N- and L-type calcium channels in NG108-15 cells, with EC₅₀S of 10 ± 2 nM and 29 ± 7 nM, respectively. The inhibition of both L- and N-type calcium channels by bradykinin (100 nM) could be completely inhibited by the bradykinin B2 receptor antagonist Hoe 140 (10 nM). Bradykinin appeared to inhibit that portion of the L-type calcium channel current that was also reversibly inhibited by ω-conotoxin GVIA. The bradykinin inhibition of the L-type calcium channel current was partly reduced by pretreatment of the cells with pertussis toxin, whereas the inhibition of the N-type current was pertussis toxin-insensitive. In some cultures it was observed that the bradykinin B1 receptor agonist desArg⁹bradykinin inhibited the L-type calcium channel current.