Activation of bradykinin B2 receptors increases calcium entry and intracellular mobilization in C9 liver cells

In C9 rat liver cells bradykinin and kallidin increased (similar to 2-fold) the intracellular concentration of calcium, but the B1 agonist, des-Arg(9) -bradykinin did not. The effect of bradykinin was inhibited by the B2 antag onists, Hoe 140 and N-alpha-adamantaneacetyl-D-Arg-[Hyp(3), Thi(5.8), D-Phe (7)]-bradykinin, but not by the BI antagonist, des-Arg(9)-[Leu(8)]-bradykin in. The action of bradykinin was diminished, but not abolished, in medium w ithout calcium. The peptide was able to increase intracellular calcium conc entration in cells treated with thapsigargin. Bradykinin action was not obs erved in cells previously stimulated with this local mediator: however, und er the same conditions, angiotensin II induced a clear increase in intracel lular calcium concentration. Our data indicate that activation of bradykinin B2 receptors increase intra cellular calcium concentrations by inducing both gating of the cation and i ntracellular mobilization in C9 liver cells. In addition, homologous desens itization was observed.