Figure 3.

(A) Chelation of intracellular Ca²⁺ promotes use-dependent rundown of KAR responses. Ca²⁺ was chelated by applying BAPTA-AM to DRG neurons for 5 min. Examples of KA-induced responses (perforated whole-cell recording) before and after application of BAPTA-AM to the bath are shown on the left and for comparison, control data (from Figure 1C) has been included in the graph (right, light gray). (B, C) Inhibition of phosphatase 2B—calcineurin—but not PP2A induces rundown of KAR-induced currents at a low activation frequency. Bars in panel C show the average values of 5–7 experiments. The specific PP2B inhibitors deltamethrin and FK506, and that of PP2A, okadaic acid, were used at 5 μM, 0.5 μM and 1 μM, respectively. ^**P<0.01; Student's t-test.