Effects of BmK AS on Nav1.2 expressed in Xenopus laevis oocytes.

In the present study, the pharmacological effects of BmK AS, a beta-like scorpion toxin on rNav1.2 alpha-subunit expressed in Xenopus laevis oocytes were investigated using a two-electrode voltage-clamp recording. It was found that the voltage dependence of rNav1.2 inactivation was significantly shifted towards positive membrane potential by 500 nM BmK AS, whereas the activation curves of rNav1.2 were unruffled at the same dosage. The inactivation curves of both slow and fast inactivation currents were positively moved about 12.8 and 9.7 mV, respectively. In addition, the persistent currents of rNav1.2 were invariable. The effects of BmK AS on the rNav1.2 inactivation were opposite to the previous results found in the peripheral sensory neurons. The results suggested that Nav1.2 might be the target of BmK AS in the central nervous system, and BmK AS might have an excitatory effect on the central neuron through enhancing Nav1.2.