Although electroacupuncture (EA) has been used to decrease the blood pressure (BP) clinically, the underlying mechanisms are not clearly clarified. This study aimed to assess the hypothesis that EA treatment exerts a hypotensive action via suppressing sympathetic activities and modulating neuropeptide Y (NPY) function within the paraventricular nucleus (PVN) of hypertensive rats. Male Sprague-Dawley rats were selected for the experiment, and the hypertensive models were established by the two-kidney, one-clip (2K1C) method. Then, the rats were randomly assigned to the sham group, 2K1C group, 2K1C plus EA group, and 2K1C plus sham EA group. EA treatment at the acupoints ST36 and ST40 overlying the peroneal nerves was given once a day for 30 days. The radiotelemetry system was applied to collect the arterial BP recordings. Power spectral analyses of BP variability, BP responses to ganglionic blockade, and plasma levels of norepinephrine and epinephrine were performed to assess the changes in sympathetic nerve activity. Real-time PCR and Western blots were carried out to examine the expression of NPY system in the PVN. The responses of PVN microinjection with NPY Y1R antagonist BIBO3304 were detected to check the endogenous NPY tone. The results showed that the enhanced arterial BP and sympathetic activities were effectively reduced by 30 days of EA treatment, and baroreflex sensitivity was improved in 2K1C hypertensive rats. The level of NPY mRNA and protein expression in the PVN was markedly upregulated by EA treatment in 2K1C rats. In addition, the pressor responses of PVN microinjection with NPY Y1R antagonist BIBO3304 in 2K1C models were remarkably augmented by the EA stimulation. Our results indicate that the increased NPY expression and function in the PVN induced by EA treatment contribute to antihypertensive and sympathetic suppression on hypertensive rats. The findings may elucidate the underlying mechanisms of the acupuncture to be a potential therapeutic strategy against hypertension.

中文翻译：

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脑室旁核内神经肽 Y 在电针抑制高血压大鼠交感神经活动中的作用

尽管电针 (EA) 已在临床上用于降低血压 (BP)，但其潜在机制尚不清楚。本研究旨在评估 EA 治疗通过抑制交感神经活动和调节高血压大鼠室旁核 (PVN) 内的神经肽 Y (NPY) 功能发挥降压作用的假设。实验选取雄性Sprague-Dawley大鼠，采用双肾一夹（2K1C）法建立高血压模型。然后将大鼠随机分为假手术组、2K1C组、2K1C加电针组、2K1C加假电针组。在腓神经上方的ST36和ST40穴位进行电针治疗，每天一次，持续30天。应用无线电遥测系统收集动脉血压记录。对 BP 变异性、BP 对神经节阻滞的反应以及去甲肾上腺素和肾上腺素的血浆水平进行功率谱分析，以评估交感神经活动的变化。采用实时荧光定量 PCR 和蛋白质印迹法检测 PVN 中 NPY 系统的表达。检测 PVN 显微注射与 NPY Y1R 拮抗剂 BIBO3304 的反应以检查内源性 NPY 音调。结果表明，电针治疗 30 天后增强的动脉血压和交感神经活动有效降低，2K1C 高血压大鼠的压力反射敏感性得到改善。在 2K1C 大鼠中，EA 处理显着上调 PVN 中 NPY mRNA 和蛋白质表达的水平。此外，EA 刺激显着增强了 PVN 显微注射与 NPY Y1R 拮抗剂 BIBO3304 在 2K1C 模型中的升压反应。我们的研究结果表明，电针治疗诱导的 PVN 中 NPY 表达和功能的增加有助于高血压大鼠的抗高血压和交感神经抑制。这些发现可能阐明针灸的潜在机制是一种潜在的高血压治疗策略。