Does pulsatile and sustained neck pressure or neck suction produce differential cardiovascular and sympathetic responses in humans?
Does pulsatile and sustained neck pressure or neck suction produce differential cardiovascular and sympathetic responses in humans?
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DOI：
10.1113/eph8802586
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发表时间：
2003-09-01
影响因子：
2.7
通讯作者：
Smith, ML
中科院分区：
文献类型：
--
作者：
Ogoh, S;Fadel, PJ;Smith, ML
虽然方波持续和R波触发的脉动刺激已被用来评估颈动脉压力感受器反射（CBR）功能在人类中，它仍然不清楚这些不同的刺激协议是否引起可比的反应，以及CBR反应是否适应在长时间的刺激。因此，我们测量了肌肉交感神经活动（MSNA），心率（HR）和平均动脉压（MAP），以响应+30托颈部压力（NP）和-30托颈部吸力（NS），持续20秒，无论是作为持续或脉动刺激。CBR介导的MSNA，HR和MAP的变化与持续和脉动刺激相似。MSNA和HR反应的时间过程表明，NP组在最初5 s内发生了显著变化，并且在20 s内比NS组保持得更好。MAP的变化在NP过程中表现出较慢的开始，峰值增加出现在10 s（持续，7 +/- 1 mmHg;脉动，7 +/- 1 mmHg; P > 0.05），NS过程中的最低值出现在20 s（持续，-7 +/- 1 mmHg;脉动，-9 +/- 2 mmHg; P > 0.05）。这些数据表明，持续和脉动NP和NS产生可比的CBR介导的反应。此外，尽管MS NA和HR在NS期间恢复至基线，但CBR介导的MAP变化在NS和NP的20秒内保持良好。
Although square-wave sustained and R wave-triggered pulsatile stimuli have been used to assess carotid baroreflex (CBR) function in humans, it remains unclear whether these different stimulus protocols elicit comparable responses and whether CBR responses adapt during prolonged stimulation. Thus, we measured muscle sympathetic nerve activity (MSNA), heart rate (HR) and mean arterial pressure (MAP) in response to +30 Torr neck pressure (NP) and -30 Torr neck suction (NS) delivered for 20 s either as a sustained or pulsatile stimulus. CBR-mediated changes in MSNA, HR and MAP were similar with sustained and pulsatile stimuli. The time course of MSNA and HR responses identified that significant changes occurred during the initial 5 s and were better maintained over 20 s with NP than with NS. Changes in MAP exhibited a slower onset with the peak increase during NP occurring at 10 s (sustained, 7 +/- 1 mmHg; pulsatile, 7 +/- 1 mmHg; P > 0.05) and the nadir during NS occurring at 20 s (sustained, -7 +/- 1 mmHg; pulsatile, -9 +/- 2 mmHg; P > 0.05). These data demonstrate that sustained and pulsatile NP and NS produce comparable CBR-mediated responses. Furthermore, despite MSNA and HR returning towards baseline during NS, CBR-mediated changes in MAP are well maintained over 20 s of NS and NP.