Mechanism behind augmentation in baroreflex sensitivity after acute exercise in spontaneously hypertensive rats
Mechanism behind augmentation in baroreflex sensitivity after acute exercise in spontaneously hypertensive rats
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DOI：
10.1291/hypres.29.117
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发表时间：
2006-02-01
影响因子：
5.4
通讯作者：
Kohzuki, M
中科院分区：
文献类型：
--
作者：
Minami, N;Mori, N;Kohzuki, M
单次动态运动增加自发性高血压大鼠（SHR）的压力反射敏感性（BRS）。我们研究了与动态运动相关的血流动力学变化（血压和心率增加）是否有助于运动后BRS的调节。用颈动脉导管和颈静脉导管对12周龄SHR进行慢性内固定。然后将他们分配到三个组中，进行40分钟的1）以12 m/min在跑步机上跑步（Run），2）同时输注异丙肾上腺素和相对高剂量的苯丙氨酸（Iso+Phe（高）），或3）同时输注异丙肾上腺素和相对低剂量的苯丙氨酸（Iso+Phe（低））。在整个实验过程中连续记录动脉压和心率。在运动前和运动后（Run组）或给药前（Iso+Phe（高）组或Iso +Phe（低）组），分别检测BRS（苯丙氨酸注射液心率反应）和SBP（交感神经活性的标志物）功率谱分析（SBP LFamp）。BRS在跑步后从1.4增加到1.9 bpm/mmHg，但在施用lso+Phe（高）或lso+Phe（低）后没有显著增加。血压和SBP-LFamp在Run、lso+Phe（高）和lso+Phe（低）组中均显著降低。这些结果表明，血流动力学的变化本身并不有助于运动后调制的BRS，而运动过程中的血流动力学变化或交感神经激活有助于运动后低血压与交感神经活动的减少。
A single bout of dynamic exercise increases baroreflex sensitivity (BRS) in spontaneously hypertensive rats (SHR). We examined whether change in hemodynamics (increases in blood pressure and heart rate) associated with dynamic exercise contribute to the post-exercise modulation of BRS. SHR aged 12 weeks were chronically instrumented with a carotid artery catheter and jugular vein catheter. They were then allocated to three groups submitted to 40 min of 1) running on a treadmill at 12 m/min (Run), 2) concomitant infusion of isoproterenol and a relatively high dose of phenylephrine (Iso+Phe(high)), or 3) concomitant infusion of isoproterenol and a relatively low dose of phenylephrine (Iso+Phe(low)). Arterial pressure and heart rate were continuously recorded throughout the experiments. BRS estimated by heart rate responses to phenylephrine injection and systolic blood pressure-low frequency power amplitude (SBP-LFamp) evaluated by power spectral analysis of SBP, a marker of sympathetic activity, were examined before and after running (Run group), or administration of drugs (Iso+Phe(high) or lso+Phe(low) groups). BRS increased significantly from 1.4 to 1.9 bpm/mmHg after running, but not after administration of lso+Phe(high) or lso+Phe(low). Blood pressure and SBP-LFamp significantly decreased in each of the Run, lso+Phe(high) and lso+Phe(low) groups. These results suggest that hemodynamic change alone does not contribute to post-exercise modulation of BRS, while hemodynamic change or sympathetic activation during exercise contributes to post-exercise hypotension associated with a reduction of sympathetic activity.