Department of Anesthesiology, Mayo Clinic, 200 1st St SW, SMH, Joseph 4-184, Rochester, MN 55905.
Hypertension. 2014 Feb;63(2):303-8. doi: 10.1161/HYPERTENSIONAHA.113.02393. Epub 2013 Dec 9.
The autonomic nervous system plays a central role in both acute and chronic blood pressure regulation in humans. The activity of the sympathetic branch of the autonomic nervous system is positively associated with peripheral resistance, an important determinant of mean arterial pressure in men. In contrast, there is no association between sympathetic nerve activity and peripheral resistance in women before menopause, yet a positive association after menopause. We hypothesized that autonomic support of blood pressure is higher after menopause in women. We examined the effect of ganglionic blockade on arterial blood pressure and how this relates to baseline muscle sympathetic nerve activity in 12 young (25±1 years) and 12 older postmenopausal (61±2 years) women. The women were studied before and during autonomic blockade using trimethaphan camsylate. At baseline, muscle sympathetic nerve activity burst frequency and burst incidence were higher in the older women (33±3 versus 15±1 bursts/min; 57±5 versus 25±2 bursts/100 heartbeats, respectively; P<0.05). Muscle sympathetic nerve activity bursts were abolished by trimethaphan within minutes. Older women had a greater decrease in mean arterial pressure (-29±2 versus -9±2 mm Hg; P<0.01) and total peripheral resistance (-10±1 versus -5±1 mm Hg/L per minute; P<0.01) during trimethaphan. Baseline muscle sympathetic nerve activity was associated with the decrease in mean arterial pressure during trimethaphan (r=-0.74; P<0.05). In summary, our results suggest that autonomic support of blood pressure is greater in older women compared with young women and that elevated sympathetic nerve activity in older women contributes importantly to the increased incidence of hypertension after menopause.
自主神经系统在人类的急性和慢性血压调节中起着核心作用。自主神经系统的交感神经分支的活动与外周阻力呈正相关，而外周阻力是男性平均动脉压的重要决定因素。相比之下，在绝经前女性中，交感神经活动与外周阻力之间没有关联，但在绝经后存在正相关。我们假设女性绝经后血压的自主支持更高。我们检查了神经节阻滞对动脉血压的影响，以及这种影响与 12 名年轻（25±1 岁）和 12 名绝经后（61±2 岁）女性基线肌肉交感神经活动之间的关系。在使用三甲噻酚 camsylate 进行自主神经阻滞之前和期间，对女性进行了研究。在基线时，老年女性的肌肉交感神经活动爆发频率和爆发发生率更高（33±3 比 15±1 次/分钟；57±5 比 25±2 次/100 次心跳，分别；P<0.05）。肌肉交感神经活动爆发在几分钟内被三甲噻酚完全抑制。老年女性在三甲噻酚期间平均动脉压下降幅度更大（-29±2 比-9±2 毫米汞柱；P<0.01），总外周阻力下降幅度更大（-10±1 比-5±1 毫米汞柱/升/分钟；P<0.01）。基线肌肉交感神经活动与三甲噻酚期间平均动脉压的下降呈负相关（r=-0.74；P<0.05）。总之，我们的研究结果表明，与年轻女性相比，老年女性对血压的自主支持更大，而老年女性的交感神经活动升高对绝经后高血压的发生率增加有重要贡献。
