Figure 1.

Run-down of ionotropic KAR activity in DRG neurons. (A) Under conventional whole-cell configuration (−30 mV holding potential), pulses of KA (50 μM, 1.5 s) were delivered at 1-min intervals. A slight rundown of KA-induced responses was observed (open symbols). Such a rundown was exacerbated by activating PKC (PdBu, 1 μM, light gray symbols). (B) The rundown of KA-induced responses was larger under perforated patch-clamp conditions (closed symbols). This rundown was prevented by inhibiting PKC (calphostin C, 50 μM, gray symbols). (C) The rundown of KA-induced currents depends on KAR activity. Under perforated whole-cell recording, the rundown of KA-induced responses was not apparent if KA pulses were delivered at 5-min intervals. (D) Summary of the data from all the experiments. ^*P<0.05, ^**P<0.01; Student's t-test.