Abstract：Abstract: Jingzhaotoxin-Ⅲ(JZTX-Ⅲ) is a gating modifier toxin isolated from Chinese tarantula Chilobrachys jingzhao venom. The toxin can selectively inhibit the activation of Nav1.5 channel, but has no inhibition effect on other sodium channel subtypes including Nav1.1~Nav1.4, Nav1.6 and Nav1.7. In order to better understand the structure-function relationships of sodium channels, the effects of JZTX-Ⅲ on Nav1.8 channels expressed in ND7/23 cells were analyzed using the whole cell patch-clamp technique. The results showed that JZTX-Ⅲ could inhibit the currents of Nav1.8 channel in a time- and concentration-dependent manner. The time constant for JZTX-Ⅲ inhibition was 41.15±0.6 s and the IC50 value was 1.4±0.23 μmol/L. The application of 1 μmol/L JZTX-Ⅲ caused a depolarized shift of the current-voltage relationship curve and activation curve by approximate 10 mV and 9 mV, respectively. Furthermore, the steady-state inactivation curve was hyperpolarizingly shifted by 16 mV. Therefore, JZTX-Ⅲ could affect the activation and inactivation characteristics of Nav1.8 channels. What’s more, amino acid sequence alignment implied that JZTX-Ⅲ might inhibit Nav1.8 channel by binding to the residue Lys(K) in the DIIS3~S4 linker of Nav1.8 channel. The findings will facilitate further investigation of the structure-function relationships of sodium channels.
引用本文:
陶 怀, 张亦雅, 陈 夏, 何迎春, 梁宋平. 敬钊毒素-Ⅲ对Nav1.8通道的抑制作用[J]. 生命科学研究, 2016, 20(3): 196-201.
TAO Huai, ZHANG Yi-Ya, CHEN Xia, HE Ying-Chun, LIANG Song-Ping. Inhibition Effects of Tarantula Toxin JZTX-III on Sodium Channel Subtype Nav1.8. Life Science Research, 2016, 20(3): 196-201.
2016, Vol. 20 
