Carotid baroreflex responsiveness during dynamic exercise in humans.
Carotid baroreflex responsiveness during dynamic exercise in humans.
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人类动态运动期间颈动脉压力反射反应。
DOI：
10.1152/ajpheart.1993.265.6.h1928
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Raven,PB
中科院分区：
文献类型：
--
作者：
Potts,JT;Shi,XR;Raven,PB
我们利用 5 秒的颈部压力和颈部吸力变化（从 40 托到 -80 托）来改变 7 名峰值摄氧量 (VO2peak) 为 41.4 +/- 3.6 ml O2.kg-1.min-1 的男性的颈动脉窦透壁压。使用心率 (HR) 和平均动脉压 (MAP) 对每个颈动脉窦扰动的峰值反应来构建休息时和运动期间 25.7 +/- 1.1 和 47.4 +/- 1.9% VO2peak 的开环压力反射曲线。压力反射曲线符合描述颈动脉窦压力感受器反射的乙状结肠性质的逻辑函数。静息时压力反射控制 HR (-0.31 +/- 0.05beats.min-1.mmHg-1) 和 MAP (-0.30 +/- 0.08 mmHg/mmHg) 的最大增益与 25% 和 50% VO2peak 运动期间相同 (-0.30 +/- 0.05、-0.39 +/- 0.13 HR 为beats.min-1.mmHg-1，P = NS；MAP 为-0.23 +/- 0.04，-0.60 +/- 0.38 mmHg/mmHg，P = NS)。压力反射的重置发生在 50% VO2peak 运动期间。压力感受反射控制 HR（δ 压力 = 26.3 +/- 6.8、19.6 +/- 10.4、33.0 +/- 5.6 mmHg，P < 0.05）和 MAP（δ 压力 = 27.1 +/- 7.7、16.1 +/- 14.8、38.2 +/- 8.5）的中心点、阈值和饱和压力显着增加毫米汞柱，P < 0.05）。在 50% VO2peak 运动期间，操作点（稳态 HR 和 MAP）更接近压力感受反射阈值，这反映在中心点和操作点之间 HR 和 MAP 的差异（δ HR = 12.5 +/- 4.7 次/分钟，P = 0.10；δ MAP = 7.6 +/- 1.3 mmHg，P < 0.05）。这些发现表明运动期间颈动脉压力感受性反射会重置，而最大敏感性没有减弱。工作点向压力反射阈值的转变可以通过 HR 和 MAP 的反射改变有效缓冲全身血压的升高。
We utilized 5-s changes of neck pressure and neck suction (from 40 to -80 Torr) to alter carotid sinus transmural pressure in seven men with peak oxygen uptake (VO2peak) of 41.4 +/- 3.6 ml O2.kg-1.min-1. Peak responses of heart rate (HR) and mean arterial pressure (MAP) to each carotid sinus perturbation were used to construct open-loop baroreflex curves at rest and during exercise at 25.7 +/- 1.1 and 47.4 +/- 1.9% VO2peak. The baroreflex curves were fit to a logistic function describing the sigmoidal nature of the carotid sinus baroreceptor reflex. Maximal gain for baroreflex control of HR (-0.31 +/- 0.05 beats.min-1.mmHg-1) and MAP (-0.30 +/- 0.08 mmHg/mmHg) at rest was the same as during exercise at 25 and 50% VO2peak (-0.30 +/- 0.05, -0.39 +/- 0.13 beats.min-1.mmHg-1 for HR, P = NS; -0.23 +/- 0.04, -0.60 +/- 0.38 mmHg/mmHg for MAP, P = NS). Resetting of the baroreflex occurred during exercise at 50% VO2peak. The centering point, threshold, and saturation pressures were significantly increased for baroreflex control of HR (delta pressure = 26.3 +/- 6.8, 19.6 +/- 10.4, 33.0 +/- 5.6 mmHg, P < 0.05) and MAP (delta pressure = 27.1 +/- 7.7, 16.1 +/- 14.8, 38.2 +/- 8.5 mmHg, P < 0.05). The operating point (steady-state HR and MAP) was shifted closer to threshold of the baroreflex during exercise at 50% VO2peak, as reflected by differences in HR and MAP between the centering and operating points (delta HR = 12.5 +/- 4.7 beats/min, P = 0.10; delta MAP = 7.6 +/- 1.3 mmHg, P < 0.05). These findings suggest a resetting of the carotid baroreflex during exercise with no attenuation in maximal sensitivity. A shift in operating point toward threshold of the baroreflex enables effective buffering of elevations in systemic blood pressure via reflex alterations in HR and MAP.