Non-motor symptoms are common in Parkinson's disease (PD) and they include dysregulation of cardiovascular system, which adversely affects quality of life. Recent studies provide indirect evidence that baroreflex dysfunction may be one of the mechanisms of cardiovascular dysregulation in PD. Herein, we tested the hypothesis that the baroreflex gain, assessed across an extensive range of the reflex arc by eliciting rapid changes in blood pressure (BP) induced by sequential boluses of vasoactive drugs (modified-Oxford technique), would be attenuated in middle-aged patients with PD. Beat-to-beat heart rate (electrocardiography) and BP (finger photoplethysmography) were obtained during 10-min of supine rest preceding the modified-Oxford [bolus of nitroprusside followed by phenylephrine 1-min afterwards] in eleven patients with PD (51±6yr) and seven age-matched controls (47±6yr). The resulting systolic BP and R-R interval responses were plotted and fitted with segmental linear regression and symmetric sigmoid model. Spontaneous indices obtained via sequence technique were also used to estimate baroreflex gain. Compared to controls, the estimated gains measured by segmental linear regression (patients: 3.83±2.6 ms/mmHg vs. controls: 7.78±1.7 ms/mmHg; P=0.003) and symmetric sigmoid model (patients: 12.36±6.9 ms/mmHg vs. controls: 32.02±19.0 ms/mmHg; P=0.009) were lower in patients with PD. The operating range of BP was larger in patients with PD compared to controls (13±7 mmHg vs. controls: 7±3 mmHg; P=0.032). Of note, the gain obtained from spontaneous indices was similar between groups. These data indicate that baroreflex gain was reduced by >50% in PD, thereby providing clear and direct evidence that cardiovagal baroreflex dysfunction occurs in PD.

中文翻译：

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帕金森病的压力反射功能：来自改良牛津技术的见解。

非运动症状在帕金森病 (PD) 中很常见，它们包括心血管系统失调，这会对生活质量产生不利影响。最近的研究提供了间接证据，表明压力反射功能障碍可能是 PD 中心血管失调的机制之一。在此，我们测试了压力反射增益的假设，通过引发连续推注血管活性药物（改良牛津技术）引起的血压 (BP) 快速变化，在广泛的反射弧范围内评估压力反射增益将在中期减弱老年 PD 患者。在 11 名 PD 患者（51±10 6 岁）和七个年龄匹配的对照（47±6 岁）。绘制得到的收缩压 BP 和 RR 间期响应，并用分段线性回归和对称 sigmoid 模型拟合。通过序列技术获得的自发指数也用于估计压力反射增益。与对照组相比，通过分段线性回归（患者：3.83±2.6 ms/mmHg vs. 对照组：7.78±1.7 ms/mmHg；P=0.003）和对称 sigmoid 模型（患者：12.36±6.9 ms/mmHg vs. . 对照：32.02±19.0 ms/mmHg；P=0.009) 在 PD 患者中较低。与对照组相比，PD 患者的血压操作范围更大（13±7 mmHg vs. 对照组：7±3 mmHg；P=0.032）。值得注意的是，从自发指数获得的收益在组间相似。这些数据表明，PD 中压力反射增益降低了 >50%，从而提供了明确和直接的证据，证明 PD 中会出现心迷走神经压力反射功能障碍。