中文摘要：

电压门控钠通道广泛分布于各类细胞和组织中,参与许多生理功能的调节。作为位于脂质双分子层的膜蛋白,周围的质膜成分对于其门控特性和药理学特性是否存在影响仍然未知。本研究采用全细胞膜片钳技术,以两种钠通道的特异性调制剂BmK I和BmK AS为研究工具,在鞘磷脂酶D作用于细胞膜后,观察ND7-23细胞系上内源表达的电压门控钠通道的门控特性和药理学特性是否发生改变。结果显示,鞘磷脂酶D作用后,电压门控钠通道的门控特性并未发生变化,但其药理学特性发生了一定程度的改变。在低浓度30 nmol/L BmK I作用后,鞘磷脂酶D的修饰使得激活曲线的斜率因子k值发生改变,且30和100 nmol/L BmK I作用后,电压依赖性的慢失活和稳态失活发生超极化偏移。同样在低浓度0.1和10 nmol/L BmK AS作用后,鞘磷脂酶D的修饰使得电压依赖性的慢失活发生超极化偏移或斜率因子k值的改变。以上结果表明,通道毒理学依赖于周围的质膜环境。证明细胞膜可以调节钠通道的药理学特性。这不仅有助于对钠通道结构与周围膜蛋白相互作用关系的进一步理解,同时也为针对钠通道相关疾病的药物研发提供有益的参考思路。

英文摘要：

Voltage-gated sodium channels（VGSCs） are widely distributed in most cells and tissues, performing many physiological functions. As one kind of membrane proteins in the lipid bilayer, whether lipid composition plays a role in the gating and pharmacological sensitivity of VGSCs still remains unknown. Through the application of sphingomyelinase D（SMase D）, the gating and pharmacological sensitivity of the endogenous VGSCs in neuroblastoma ND7-23 cell line to BmK I and BmK AS, two sodium channel-specific modulators from the venom of Buthus martensi Karsch（BmK）, were assessed before and after lipid modification. The results showed that, in ND7-23 cells, SMase D did not change the gating properties of VGSCs. However, SMase D application altered the slope factor of activation with the treatment of 30 nmol/L BmK I, but caused no significant effects at 100 and 500 nmol/L BmK I. With low concentration of BmK I（30 and 100 nmol/L） treatment, the application of SMase D exerted hyperpolarizing effects on both slow-inactivation and steady-state inactivation, and increased the recovery time constant, whereas total inactivation and recovery remained unaltered at 500 nmol/L Bm K I. Meanwhile, SMase D modulation hyperpolarized the voltage dependence of slow-inactivation at 0.1 nmol/L BmK AS and altered the slope factor of slow-inactivation at 10 nmol/L BmK AS, whereas other parameters remained unchanged. These results indicated a possibility that the lipid bilayer would disturb the pharmacological sensitivity of VGSCs for the first time, which might open a new way of developing new drugs for treating sodium channelopathies.