Figure 2. Single-cell application of Na_v Abs inhibits SNc DA neuron activity and decreases excitability.

(A) Na_v1.1 Ab (secondary antibody only) and TH immunostaining in SNc after whole-cell recording; Na_v1.2 Ab immunostaining is illustrated in Figure S1B. Neurobiotin 488 was introduced with Na_v1.1 Ab via the recording pipette (n = 5 slices). Scale bar, 20 μm.

(B) Time course of spontaneous SNc DA neuron firing frequency over 25 min with intracellular application of vehicle (n = 5), IgG (n = 5), or Na_v1.1 Ab + Na_v1.2 Ab (Na_v Abs) (n = 7).

(C) Spontaneous activity with vehicle, IgG, or Na_v Abs in the pipette.

(D) Summary of Na_v Ab effects on spontaneous frequency (vehicle, 99% ± 23% of initial frequency, n = 5, p = 0.5; IgG, 79% ± 13%, n = 5, p = 0.15; Na_v1.1 Ab and Na_v1.2 Ab, 14% ± 5%, n = 7, **p < 0.01; paired t test).

(E) Spontaneous activity with Na_v Abs in the pipette; Δt is the time from resting membrane voltage (V_m) to AP threshold (AP_threshold).

(F) Quantification of Δt when recorded with Na_v Abs in the pipette (initial, 0.22 ± 0.07 s; final, 0.71 ± 0.04 s, ***p < 0.001). Bars are means ± SEM for n = 4; paired t test.

(G) Response of SNc DA neurons recorded in current clamp during depolarizing current injection (+400 pA, 200 ms) after establishing whole-cell recording (initial) and the end of 25-min recording (final) with Na_v Abs in the pipette. Intracellular application of Na_v Abs decreased the number of APs evoked by current injection.

(H) Time course of the effect of single-cell application of Na_v Abs on AP number evoked during current injection (vehicle, n = 6; Na_v Abs, n = 5).

(I) AP number during current injection with vehicle or Na_v Abs in the pipette (vehicle, 106% ± 9% of initial, n = 6, p = 0.4; Na_v Abs, 64% ± 7%, n = 5, *p < 0.05; paired t test).