Multi-walled carbon nanotube increases the excitability of hippocampal CA1 neurons through inhibition of potassium channels in rat's brain slices.

This study was to investigate the neurotoxicity of multi-walled carbon nanotube (MWCNT) by measuring neuronal excitability in rat hippocampal neurons and exploring the underlying mechanism. Whole cell patch-clamp technique was used. Action potential properties and the pattern of repetitive firing rate were assessed. Our data showed that spike half-width and repetitive firing rate were significantly increased in a concentration-dependent manner. Furthermore, voltage-activated potassium currents were recorded. It was found that MWCNT produced a concentration-dependent inhibition in amplitudes of I(A) and I(K). In addition, MWCNT had effect on the activation kinetics of I(A) and I(K) with V(h) being shifted to the negative potential at high concentration, while I(A) inactivation curve was considerably shifted to the hyperpolarize potential with V(h) being increased. However, no effect was found on the recovery from inactivation of I(A). The results suggest that MWCNT increases the excitability of hippocampal CA1 neurons by inhibiting voltage-gated potassium current.