Modulation of Nano-Selenium on Tetrodotoxin-Sensitive Voltage-Gated Sodium Currents in Rat Dorsal Root Ganglion Neurons

Nano-selenium, a novel nano technology production, was demonstrated to be useful in medical and scientific researches. Here, we investigated the effects of nano-Selenium on tetrodotoxin-sensitive (TTX-S) voltage-dependent Na⁺ channels in isolated rat dorsal root ganglion neurons, using whole-cell patch-clamp method. Nano-selenium irreversibly decreased TTX-S Na⁺ current (I_Na) in a concentration-dependent manner and shifted the maximum of the current/voltage relationship from -67mV to -52mV, without modifying the threshold potential of the current. Nano-selenium shifted the steady-state activation and inactivation curves to the left. In the contrast of Na₂SeO₃, the inhibition effect of 1nM nano-Se was much stronger. The cell treated with 1nM Na₂SeO ₃ firstly, still respond to further addition of 1nM nano-selenium. These results prove nano-selenium to be a novel antagonist, acted within the channel pore, not on or near the exterior surface of the channel protein where it would experience the membrane electric field, which possesses a distinct binding site from Na₂ SeO₃