Figure 4. Single A- and DR-channels in dorsal horn neurones.

A, recordings of A-channels in inside-out patches. The pipettes were filled with high-${\text{K}}_{\text{o}}^{+}$ solution and the bath contained high-${\text{K}}_{\text{i}}^{\text{+o}}$ solution. Holding potential was -80 mV. The channels were activated by voltage steps to -40 or +40 mV after a 150 ms prepulses to -120 mV. The channel conductance was about 50 pS for inward currents and 30 pS for outward currents. B, recordings of single DR-channel currents. Inside-out patch. Holding potential was -80 mV. The channels were activated by a voltage pulse to +40 mV following a 150 ms prepulse to -60 mV inactivating A-channels. High-K⁺ solutions on both sides of the membrane. The channel conductance was 24-30 pS for inward currents and about 20 pS for outward currents.