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<inf>Na</inf>) 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 Na<inf>2</inf>SeO<inf>3</inf>, the inhibition effect of 1nM Nano-Se was much stronger. The cell treated with 1nM Na<inf>2</inf>SeO<inf>3</inf>firstly, still respond to futher addition of 1nM Nano-Selenium. These results prove Nano-Selenium to be a novel antiagonist, 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 Na<inf>2</inf>SeO<inf>3</inf>.