Channels In Dorsal Root Ganglion Neurons Moe Key Lab Of Modern Toxicology Nanjing Medical University

Part one: Toxic effects of BmK224 on PC12 cellsThe technique of CCK-8 was applied to explore toxic effects of BmK224 on PC12 cells. PC12 cells were treated by BmK224 with different doses for 24h, and their changes were estimated by CCK-8 assay. The result suggested that the Cellular proliferation was not changed with the concentration of BmK224 raised up (P>0.05).Part two: Effects of BmK224 on action potential in rat dorsal root ganglion neurons(DRG)Action potential (AP) was successfully recorded in freshly isolated DRG neurons using whole-cell patch clamp technique. We investigated the effects of BmK224 on APs in rat DRG neurons. The results showed BmK224 could inhibit APs firing.The firing frequency and the amplitude of APs were decreased with 40μg/ml BmK224.Part three: Effects of BmK224 on sodium currents in rat dorsal root ganglion neurons The effects of BmK224 on voltage-depedent sodium currents (I_Na) including TTX-S I_Na and TTX-R I_Na were studied in DRG neurons using the patch-clamp technique in the whole-cell configuration. The results showed that BmK224 could inhibit the amplitudes of both TTX-S I_Na and TTX-R I_Na in a concentration- and voltage-dependent manner. At a concentration of 40μg/ml BmK224 lowered the activation threshold and produced negative shifting of TTX-S I_Na activation curve, induced shifting of the steady-state inactivation curve to left, delayed the recovery of TTX-S I_Na from inactivation, but increased the fraction of available sodium channels. At a concentration of 40μg/ml BmK224 produced positive shifting of TTX-R I_Na activation curve, induced shifting of the steady-state inactivation curve to left, delayed the recovery of TTX-R I_Na from inactivation, and also reduced the fraction of available sodium channels.Part four: Effects of BmK224 on potassium currents in rat dorsal root ganglion In this part, we observed the effects of BmK224 on the voltage dependent potassium channels in rat dorsal root ganglion neurons using whole-cell patch clamp technique. The results indicated as follows: even at 80μg/ml BmK224 did not exert significant effects on the potassium channels and the peak K⁺ currents (I_K).