Sayk Friedhelm, Becker Christoph, Teckentrup Christina, Fehm Horst-Lorenz, Struck Jan, Wellhoener Jens Peter, Dodt Christoph
Clinic for Internal Medicine I, University Hospital of Schleswig-Holstein, Luebeck, Germany.
Hypertension. 2007 May;49(5):1070-6. doi: 10.1161/HYPERTENSIONAHA.106.084343. Epub 2007 Mar 12.
That sleep is accompanied by a blood pressure decrease is well known; however, the underlying physiology deserves further investigation. The present study examines in healthy subjects 2 main questions: is this dipping actively evoked? and what are the consequences of nondipping for daytime blood pressure? Nocturnal blood pressure was extrinsically elevated in 12 sleeping subjects to mean daytime values by continuously infused phenylephrine. This nondipping significantly lowered morning blood pressure during rest and 3 hours after resuming physical activity compared with a control condition (isotonic saline). Neither muscle sympathetic nerve activity nor sensitivity of alpha-adrenoceptors was reduced. However, the set point for initiation of regulatory responses through the baroreflex was clearly shifted toward lower blood pressure levels. Our results support the hypothesis of an actively regulated central mechanism for blood pressure resetting and set point consolidation of the baroreflex during nighttime sleep. This is suggested by the fact that extrinsically induced nondipping induces sustained decrease in blood pressure during the following morning through an actively lowered baroreflex set point.
睡眠伴随着血压下降这一点是众所周知的；然而，其潜在的生理学机制值得进一步研究。本研究在健康受试者中考察了两个主要问题：这种血压下降是主动诱发的吗？血压非勺型变化对日间血压有什么影响？通过持续输注去氧肾上腺素，使12名睡眠中的受试者夜间血压外在性升高至日间平均水平。与对照情况（等渗盐水）相比，这种非勺型变化显著降低了休息时以及恢复体力活动3小时后的早晨血压。肌肉交感神经活动和α-肾上腺素能受体敏感性均未降低。然而，通过压力反射启动调节反应的设定点明显向较低血压水平偏移。我们的结果支持这样一种假设，即在夜间睡眠期间存在一种主动调节的中枢机制，用于血压重置和压力反射设定点巩固。外在诱导的非勺型变化通过主动降低的压力反射设定点在接下来的早晨导致血压持续下降，这一事实表明了这一点。
