Oxaliplatin Modulates the Characteristics of Voltage-Gated Calcium Channels and Action Potentials in Small Dorsal Root Ganglion Neurons of Rats
Oxaliplatin Modulates the Characteristics of Voltage-Gated Calcium Channels and Action Potentials in Small Dorsal Root Ganglion Neurons of Rats
复制标题
DOI：
10.1007/s12035-018-1029-5
复制
发表时间：
2018-12-01
影响因子：
5.1
通讯作者：
Hagenacker, Tim
中科院分区：
文献类型：
--
作者：
Schmitt, Linda-Isabell;Leo, Markus;Hagenacker, Tim
奥沙利铂对治疗结直肠癌很重要。虽然奥沙利铂非常有效，但它具有严重的副作用，其中背根神经节（DRG）神经元的神经毒性是最常见的副作用之一。这种神经毒性的关键机制仍然存在争议。然而，DRG神经元中钙稳态的紊乱被认为介导了奥沙利铂的神经毒性。采用全细胞膜片钳和电流钳技术以及免疫细胞化学染色，我们研究了短期和长期暴露于奥沙利铂对体外培养的大鼠小DRG神经元电压门控钙通道（VGCC）及其不同亚型的影响。奥沙利铂暴露以浓度依赖性方式降低VGCC电流（I-Ca（V））（1- 500 M; 13.8-63.3%）。VGCC的亚型特异性测量显示对I-Ca（V）的不同影响。虽然奥沙利铂急性治疗导致P/Q型、T型和L型VGCC的I-Ca（V）降低，但N型VGCC的I-Ca（V）不受影响。奥沙利铂（10或100 M）处理DRG神经元24 h后，I-Ca（V）电流密度显著增加，对L型和T型VGCC有显著影响。免疫染色显示奥沙利铂暴露后24小时DRG神经元中L型和T型VGCC蛋白水平增加。这种作用由钙-钙调蛋白-蛋白激酶II（CaMKII）介导。还观察到动作电位（AP）及其特征的显著改变。虽然奥沙利铂治疗后振幅增加，但上升时间和达峰时间减少，并且这些作用通过匹莫齐特和尼莫地平治疗逆转，这表明VGCC与奥沙利铂介导的神经毒性密切相关。
Oxaliplatin is important for treating colorectal cancer. Although oxaliplatin is highly effective, it has severe side effects, of which neurotoxicity in dorsal root ganglion (DRG) neurons is one of the most common. The key mechanisms of this neurotoxicity are still controversial. However, disturbances of calcium homeostasis in DRG neurons have been suggested to mediate oxaliplatin neurotoxicity. By using whole-cell patch-clamp and current-clamp techniques, as well as immunocytochemical staining, we examined the influence of short- and long-term exposure to oxaliplatin on voltage-gated calcium channels (VGCC) and different VGCC subtypes in small DRG neurons of rats in vitro. Exposure to oxaliplatin reduced VGCC currents (I-Ca(V)) in a concentration-dependent manner (1-500M; 13.8-63.3%). Subtype-specific measurements of VGCCs showed differential effects on I-Ca(V). While acute treatment with oxaliplatin led to a reduction in I-Ca(V) for P/Q-, T-, and L-type VGCCs, I-Ca(V) of N-type VGCCs was not affected. Exposure of DRG neurons to oxaliplatin (10 or 100M) for 24h in vitro significantly increased the I-Ca(V) current density, with a significant influence on L- and T-type VGCCs. Immunostaining revealed an increase of L- and T-type VGCC protein levels in DRG neurons 24h after oxaliplatin exposure. This effect was mediated by calcium-calmodulin-protein kinase II (CaMKII). Significant alterations in action potentials (AP) and their characteristics were also observed. While the amplitude increased after oxaliplatin treatment, the rise time and time-to-peak decreased, and these effects were reversed by treatment with pimozide and nimodipine, which suggests that VGCCs are critically involved in oxaliplatin-mediated neurotoxicity.