Fig. 5. Control of brain slice L5 pyramidal neurons by HwTxIV-Nvoc.

a Inhibition of AP by 500 nM non-caged HwTxIV (n = 6). b AP in control condition, in presence of 2.5 µM HwTxIV-Nvoc and 1 min after uncaging. c Left: mean ± SEM (n = 8 cells) of normalized AP peak after addition of HwTxIV-Nvoc and 1 min after photolysis (*p = 0.0078, two-sided paired t test). Right: mean ± SEM (n = 5 cells) of normalized AP width after addition of HwTxIV-Nvoc. d APs 1 min after HwTxIV-Nvoc uncaging over a spot centered ~100 µm from the cell body or over the soma. e Mean ± SEM (n = 4 cells) of the normalized AP peak after uncaging 100 µm away from the soma or directly on the soma. (*p = 0.0005, two-sided paired t test). f Image of the ~40 µm diameter UV spot. Purple curve represents the light intensity profile on cell schematic. g Top: images of a L5 pyramidal neuron relative to UV (405 nm) illumination spot position. Bottom: AP in the presence of HwTxIV-Nvoc (orange traces) and 1 min after uncaging (purple traces) with cell positioned at 100, 80, 60, 40, 20, and 0 µm distance from spot. h Mean ± SEM (n = 5 cells) of normalized AP peak 1 min after uncaging with the cell positioned at decreasing distances from spot center (100 µm; 80 µm, p = 0.2302; 60 µm, *p = 0.0434; 40 µm, *p = 0.0420; 20 µm, *p = 0.0133; 0 µm, ***p < 0.0001). Two-sided paired t-test. i Left, L5 pyramidal neuron filled with 500 µM of ING-2. AIS area of Δ[Na⁺] measurement in red cylinder. Right, images before and during UV uncaging pulse illustrating photolysis area. j Left, somatic AP (top) and associated Δ[Na⁺] signal in the presence of HwTxIV-Nvoc. Right, after toxin uncaging, the cell was depolarized to +20 mV to correspond to control AP peak and measure Δ[Na⁺] signal in the same condition. k mean ± SEM (n = 4 cells) of the Δ[Na⁺] signal maximum (peak) before and after uncaging the toxin. (*p < 0.0174, two-sided paired t-test). Source data are provided as a Source Data File.