Increases in central blood volume modulate carotid baroreflex resetting during dynamic exercise in humans.
Increases in central blood volume modulate carotid baroreflex resetting during dynamic exercise in humans.
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人体动态运动期间，中心血容量的增加可调节颈动脉压力感受反射的重置。
DOI：
10.1113/jphysiol.2006.125112
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Raven,PeterB
中科院分区：
文献类型：
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作者：
Ogoh,Shigehiko;Fisher,JamesP;Fadel,PaulJ;Raven,PeterB
我们试图确定运动期间颈动脉-血管舒缩性压力反射功能曲线的重置是否受到中枢血容量（CBV）变化的调节。在运动过程中，CBV通过改变：(1)受试者姿势（仰卧对直立）和(2)踏板频率（80对60转/分钟（r.p.m.））而增加；而摄氧量（）保持不变。8名男性受试者进行了3项运动试验：每晚60分钟直立骑自行车（对照组）；仰卧骑行每分钟60转（SupEX）和直立骑行每分钟80转（80EX）以增强肌肉泵。在每种情况下，采用快速颈压（NP）和颈吸（NS）方案测定颈动脉压力反射（CBR）功能。尽管在所有运动条件下，平均动脉压（MAP）均较静止状态显著升高（88±2 mmHg） （P< 0.001），但在SupEX（94±2 mmHg）和80EX（95±2 mmHg）期间，MAP的升高幅度低于对照组（105±2 mmHg，P< 0.05）。重要的是，血压对NP和NS的反应维持在这些改变的MAP操作点周围。然而，与对照组相比，当CBV在SupEX和80EX期间增加时，颈动脉-血管舒缩性压力反射功能曲线向下和向左移动。这些CBR重置的改变在不同运动条件下的心率没有任何差异。因此，增加CBV和增加心肺压力反射可以降低运动引起的MAP和CBR重置增加的幅度。这些发现表明，心肺压力感受器负荷的变化会影响动态运动期间颈动脉压力反射的重置。
We sought to determine if resetting of the carotid‐vasomotor baroreflex function curve during exercise is modulated by changes in central blood volume (CBV). CBV was increased during exercise by altering: (1) subject posture (supineversusupright) and (2) pedal frequency (80versus60 revolutions min−1(r.p.m.)); while oxygen uptake () was kept constant. Eight male subjects performed three exercise trials: upright cycling at 60 r.p.m. (control); supine cycling at 60 r.p.m. (SupEX) and upright cycling at 80 r.p.m. to enhance the muscle pump (80EX). During each condition, carotid baroreflex (CBR) function was determined using the rapid neck pressure (NP) and neck suction (NS) protocol. Although mean arterial pressure (MAP) was significantly elevated from rest (88 ± 2 mmHg) during all exercise conditions (P< 0.001), the increase in MAP was lower during SupEX (94 ± 2 mmHg) and 80EX (95 ± 2 mmHg) compared with control (105 ± 2 mmHg,P< 0.05). Importantly, the blood pressure responses to NP and NS were maintained around these changed operating points of MAP. However, in comparison to control, the carotid‐vasomotor baroreflex function curve was relocated downward and leftward when CBV was increased during SupEX and 80EX. These alterations in CBR resetting occurred without any differences in or heart rate between the exercise conditions. Thus, increasing CBV and loading the cardiopulmonary baroreflex reduces the magnitude of exercise‐induced increases in MAP and CBR resetting. These findings suggest that changes in cardiopulmonary baroreceptor load influence carotid baroreflex resetting during dynamic exercise.