1：Experimental Design and Method Selection:

The study used patch-clamp method to investigate NaV

2：8 channel voltage sensitivity and organotypic nerve tissue culture to assess neurite growth. The Almers' limiting-slope procedure was applied to evaluate the effective charge (Zeff) of NaV8 channel activation gating system. Sample Selection and Data Sources:

Dissociated sensory neurons from dorsal root ganglia of newborn Wistar rats and explants from 10-12 days old chicken embryos were used.

3：List of Experimental Equipment and Materials:

CO2 laser (wavelength

4：6 μm), IMO-2N power meter, patch-clamp L/M-EPC 7 amplifier, Axio Observer Z1 microscope, semiconductor laser (wavelength 635 μm), optical wedges, mechanical screens, disk attenuator, mirrors, diaphragms, water filter, Petri dishes, collagen-coated dishes, СО2-incubator (Sanyo), reagents from Sigma. Experimental Procedures and Operational Workflow:

For patch-clamp, neurons were irradiated with low-power IR radiation (energy density 1*10^-11 J/cm2) with or without Src kinase inhibitor PP2 (10 μM). Ionic currents were recorded, and Zeff was calculated. For organotypic culture, explants were irradiated (energy density 2*10^-10 J/cm2) with or without PP2, and neurite growth was assessed by area index.

5：Data Analysis Methods:

Statistical analysis used one-way ANOVA followed by Tukey's test. Zeff was evaluated using the Almers' limiting-slope procedure. Image analysis used ImageJ and ZEN_2012 software.