College of Korean Medicine, Daegu Haany University, Daegu, 42158, South Korea.
Clinical Medicine Division, Korea Institute of Oriental Medicine, Daejeon, 34054, South Korea.
Sci Rep. 2018 Oct 8;8(1):14967. doi: 10.1038/s41598-018-33402-1.
High blood pressure (BP) is a highly controllable risk factor for cardiovascular diseases; however, awareness of this condition and the rates of controlled hypertension are low. Experimental animal studies have shown that stimulation of the median nerve or PC6 acupoint over the wrist has effects on cardiovascular activities, including reductions in systolic and diastolic BPs. A proof-of-concept study was conducted in humans to investigate whether stimulation of median nerve near PC6 acupoint decreased high BP, identify the optimal stimulation parameters for the BP-lowering effects of median nerve stimulation, and determine the specific peripheral nerves or types of afferent fibers mediating the BP-lowering effects. Median nerve stimulation was carried out bilaterally or unilaterally with different stimulation parameters, and the BP and heart rate were monitored. The afferent mechanisms underlying the effects of median nerve stimulation on hypertension were investigated via microneurography, A-fiber blocking experiments, and localized chemical or electrical stimulation. Bilateral median nerve stimulation at either low or high frequencies produced profound but transient reductions in systolic BP, which were elicited when median nerve stimulation was unilaterally applied at interelectrode distances of 2 and 4 cm. Systolic BP was also reduced by electrical stimulation of the thumb on the palm side. Although microneurographic recordings revealed the excitation of both A- and C-fibers following median nerve stimulation, the median nerve-mediated reductions in BP were not affected by A-fiber blockade, and they were mimicked by the activation of C-fibers with capsaicin. The present results indicate that activation of C-fibers in the median nerve generates BP-lowering effects in humans. Based on our clinical study, an optimized median nerve stimulator was built and combined with a wrist BP monitor for simultaneous BP measurements and median nerve stimulation.
高血压（BP）是心血管疾病的高度可控风险因素；然而，人们对这种疾病的认识和高血压的控制率都很低。实验动物研究表明，刺激正中神经或腕部的 PC6 穴位对心血管活动有影响，包括降低收缩压和舒张压。一项概念验证研究在人类中进行，以调查刺激 PC6 穴位附近的正中神经是否可以降低高血压，确定正中神经刺激降压作用的最佳刺激参数，并确定介导降压作用的特定外周神经或传入纤维类型。双侧或单侧用不同的刺激参数进行正中神经刺激，并监测血压和心率。通过微神经记录、A 纤维阻断实验以及局部化学或电刺激研究了正中神经刺激对高血压影响的传入机制。低频或高频双侧正中神经刺激产生了深刻但短暂的收缩压降低，当单侧应用电极距离为 2 和 4 cm 时会引起这种降低。手掌侧拇指电刺激也会降低收缩压。尽管微神经记录显示正中神经刺激后 A 和 C 纤维均被兴奋，但 A 纤维阻断对正中神经介导的血压降低没有影响，并且辣椒素激活 C 纤维可以模拟这种作用。这些结果表明，激活正中神经中的 C 纤维可在人类中产生降压作用。基于我们的临床研究，构建了优化的正中神经刺激器，并与腕部血压监测器结合，用于同时进行血压测量和正中神经刺激。
