All Rbp4-Cre neurons display voltage gated sodium channels dependent active conductances, at both E14.5 and E18.5, related to Figure 4
(A–D) All Rbp4-Cre neurons (A, C), but not all nearby unlabeled cells (B, D), display active conductances, at both E14.5, and E18.5. Voltage responses (top) of an Rbp4-Cre neuron and a nearby unlabeled cell at E14.5 (A and B) and E18.5 (C and D) to graded intracellular current injections (middle), recorded in current clamp mode. The voltage responses to current are quantified in both current-voltage curves and the peak voltage compared to the steady-state voltage (as in Figure 4C) for both Rbp4-Cre neurons (C) and nearby unlabeled neurons (D), to visualize any nonlinearity in the peak voltage response. The line type labels the embryonic layer in which each recorded neuron was found (E14.5: Dotted: superficial layer, solid: deep layer; E18.5: Solid: intermediate layer). Due to visibility at E18.5, it was not possible to record from deep layer neurons. n = number of neurons.
(E) Left: schematic of para-uterine imaging combined with patch clamp recording to perform in vivo two-photon targeted electrophysiology from Rbp4-Cre neurons together with application of TTX. Right: Voltage responses of an Rbp4-Cre neuron (at E14.5 (top) and E18.5 (bottom)) to graded intracellular current injections, recorded in current clamp mode before (left, pre) and after (right, post) application of TTX. Scale bar: 10 mV (top, A), 50 ms and 20 pA (middle, A), 10 mV (top, B), 50 ms and 20 pA (middle, B), 10 mV (top, C), 50 ms and 20 pA (middle, C), 10 mV (top, D), 50 ms and 20 pA (middle, D), 20 mV (top, E), 10 ms and 40 pA (bottom, E).