Bradykinin evokes a Ca²⁺‐activated chloride current in non‐neuronal cells isolated from neonatal rat dorsal root ganglia

Abstract

We have studied the effect of bradykinin (Bk) on fibroblast-like satellite (FLS) cells isolated from cultures of neonatal rat dorsal root ganglia (DRG). In voltage-clamped FLS cells Bk evoked an inward current response that was concentration dependent with a half-maximal concentration of 2 nM. In indo-1 AM-loaded FLS cells Bk evoked a rise in intracellular Ca2+ that was concentration dependent with a half-maximal concentration of 1 nM. The FLS cells still produced an inward current in response to Bk in the absence of extracellular Ca2+ but the response was inhibited if the intracellular concentration of EGTA was increased from 0.5 to 5 mM, which suggests that the inward current was dependent on the release and subsequent rise of intracellular Ca2+. The reversal potential of the Bk-induced inward current was consistent with the current being due to an increase in Cl- conductance and shifted in a Nernstian manner when the intracellular Cl- concentration was reduced. The inward current response to Bk was blocked by the B2 receptor antagonist HOE-140, which indicates that the response was due to activation of B2 receptors. The data suggest that Bk evokes a rise in intracellular Ca2+ and activation of a Ca2+-activated Cl- conductance in the FLS cells and raise the possibility that FLS cells contribute to the pro-inflammatory effects of Bk in DRG.