Fig. 2. Effects of meperidine on voltage-activated K⁺currents. Multiple channel K^DRcurrents in an outside-out patch responding to a test pulse to 0 mV from a holding potential of −90 mV. The pulse protocol is given above the traces. Traces show averages of 20 recordings of the K^DRcurrent in control solution and 100 μM, 1 mM, and 3 mM meperidine and after wash. Bath, Ri-TTX; pipette, K^Cli.