Modulation of BmK AS, a scorpion neurotoxic polypeptide, on voltage-gated Na+ channels in B104 neuronal cell line.

The modulation of BmK AS, a neurotoxic polypeptide from scorpion Buthus martensi Karsch, on the voltage-gated Na(+) channels has been investigated in the B104 neuroblastoma cell line by whole-cell patch clamping. It was found that the whole Na(+) currents and tetrodotoxin-resistant Na(+) current were depressed in a biphasic manner and both steady-state activation and inactivation curves were shifted toward the hyperpolarizing direction in the presence of BmK AS. The results suggested that BmK AS could inhibit both tetrodotoxin-sensitive and -resistant Na(+) currents via modulating the gating mechanism of the voltage-gated Na(+) channels in B104 cells.