General excitability and I
currents in spinal cord are identical in wild type and L1 mice. (A) Mean number of action potentials obtained in current clamp recordings in response to depolarizing current pulses of different intensities. Wild type (wt) and L1 mice show similar behaviour. (B) The two-step protocol used to isolate IA current. Superimposed current (upper) and voltage (lower) traces (left) and current isolated by subtraction in control (upper) and after perfusion of 4-AP (lower) recordings (right) is shown. (C and D) Recordings obtained from dorsal horn neurons in control conditions show voltage-dependency of inactivation (C) and recovery from inactivation (D) of transient currents. (E, F) Analysis of the IA current in dorsal horn neurons in wild type (wt) and L1 mice. Transient currents show the same characteristics in both groups in terms of activation (E, right axis conductance) and inactivation kinetics (E, left axis current) and recovery from inactivation (conductance) (F). Graphs in E show pooled data of dorsal horn neurons from wild type (n = 18) and L1 (n = 6) mice. Graphs in F were obtained from neurons from wild type (n = 5) and L1 (n = 3) mice.