Voltage-gated sodium channels are currently recognized as one of the targets of analgesics. Magnolol (Mag), an active component isolated from Magnolia officinalis, has been reported to exhibit analgesic effects. The objective of this study was to investigate whether the analgesic effect of Mag was associated with blocking Na⁺ channels. Inflammatory pain was induced by the injection of carrageenan into the hind paw of mice. Mag was administered orally. Mechanical hyperanalgesia was evaluated by using von Frey filaments. Na⁺ currents and neuronal excitability in acutely isolated mouse dorsal root ganglion (DRG) neurons were recorded with the whole-cell patch clamp technique. Results showed that Mag (10 ~ 40 mg/kg) dose-dependently inhibited the paw edema and reduced mechanical pain in the inflammatory animal model. Injection of carrageenan significantly increased the amplitudes of TTX-sensitive and TTX-resistant Na⁺ currents. Compared with the carrageenan group, Mag inhibited the upregulation of two types of Na⁺ currents induced by carrageenan in a dose-dependent manner. Mag 40 mg/kg shifted the inactivation curves of two types of Na⁺ currents to hyperpolarization and returned to normal animal level without changing their activation curves. Mag 40 mg/kg significantly reduced the percentage of cells firing multiple spikes and inhibited the neuronal hyperexcitability induced by carrageenan. Our data suggest that the analgesic effect of Mag may be associated with a decreased neuronal excitability by blocking Na⁺ current.

电压门控钠通道目前被认为是镇痛药的靶点之一。厚朴酚 (Mag) 是一种从厚朴中分离的活性成分，据报道具有镇痛作用。本研究的目的是调查 Mag 的镇痛作用是否与阻断 Na ⁺通道有关。通过将角叉菜胶注射到小鼠的后爪中来诱导炎性疼痛。Mag 是口服给药。机械痛觉过敏通过使用 von Frey 细丝进行评估。钠⁺使用全细胞膜片钳技术记录急性分离的小鼠背根神经节 (DRG) 神经元中的电流和神经元兴奋性。结果表明，Mag (10 ~ 40 mg/kg) 剂量依赖性地抑制炎症动物模型中的爪水肿并减轻机械疼痛。注射角叉菜胶显着增加了 TTX 敏感和 TTX 抗性 Na ⁺电流的幅度。与角叉菜胶组相比，Mag以剂量依赖性方式抑制角叉菜胶诱导的两种 Na ⁺电流的上调。Mag 40 mg/kg 移动了两种 Na ⁺的灭活曲线电流超极化并恢复到正常动物水平而不改变它们的激活曲线。Mag 40 mg/kg 显着降低了发射多个尖峰的细胞百分比，并抑制了角叉菜胶诱导的神经元过度兴奋。我们的数据表明，Mag 的镇痛作用可能与通过阻断 Na ⁺电流降低神经元兴奋性有关。