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首页> 外文期刊>American Journal of Physiology >Circadian periodicity of cerebral blood flow revealed by laser-Doppler flowmetry in awake rats: relation to blood pressure and activity.
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Circadian periodicity of cerebral blood flow revealed by laser-Doppler flowmetry in awake rats: relation to blood pressure and activity.

机译：激光多普勒血流仪揭示清醒大鼠脑血流的昼夜周期：与血压和活动的关系。

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摘要

Cardiovascular parameters such as arterial blood pressure (ABP) and heart rate display pronounced circadian variation. The present study was performed to detect whether there is a circadian periodicity in the regulation of cerebral perfusion. Normotensive Sprague-Dawley rats (SDR, approximately 15 wk old) and hypertensive (mREN2)27 transgenic rats (TGR, approximately 12 wk old) were instrumented in the abdominal aorta with a blood pressure sensor coupled to a telemetry system for continuous recording of ABP, heart rate, and locomotor activity. After 5-12 days, a laser-Doppler flow (LDF) probe was attached to the skull by means of a guiding device to measure changes in brain cortical blood flow (CBF). After the animals recovered from anesthesia, measurements were taken for 3-4 days. The time series were analyzed with respect to the midline estimating statistic of rhythm (i.e., mean value of a periodic event after fit to a cosine function), amplitude, and acrophase (i.e., phase angle that corresponds to the peak of a given period) of the 24-h period. The LDF signal displayed a significant circadian rhythm, with the peak occurring at around midnight in SDR and TGR, despite inverse periodicity of ABP in TGR. This finding suggests independence of LDF periodicity from ABP regulation. Furthermore, the acrophase of the LDF was consistently found before the acrophase of the activity. From the present data, it is concluded that there is a circadian periodicity in the regulation of cerebral perfusion that is independent of circadian changes in ABP and probably is also independent of locomotor activity. The presence of a circadian periodicity in CBF may have implications for the occurrence of diurnal alterations in cerebrovascular events in humans.
机译：心血管参数，例如动脉血压（ABP）和心率显示明显的昼夜节律变化。进行本研究以检测在脑灌注调节中是否存在昼夜周期。将血压正常的Sprague-Dawley大鼠（SDR，大约15 wk老）和高血压（mREN2）27转基因大鼠（TGR，大约12 wk老）装在腹主动脉中，其血压传感器与遥测系统相连，用于连续记录ABP ，心率和运动能力。 5-12天后，通过引导装置将激光多普勒血流（LDF）探针连接到颅骨，以测量大脑皮层血流（CBF）的变化。动物从麻醉中恢复后，进行3-4天的测量。针对节奏的中线估计统计量分析了时间序列，即节奏（即，拟合余弦函数后的周期性事件的平均值），幅度和前相位（即，与给定时间段的峰值相对应的相角）在24小时内LDF信号显示出明显的昼夜节律，尽管ABP在TGR中呈反周期，但峰值出​​现在SDR和TGR的午夜左右。这一发现表明LDF周期不受ABP调节的影响。此外，在活动的顶峰相一致之前一直发现LDF的顶相。从目前的数据可以得出结论，在脑灌注的调节中存在昼夜节律周期，其独立于ABP的昼夜节律变化，并且也可能不依赖于运动活动。 CBF中昼夜节律的存在可能与人类脑血管事件的昼夜变化发生有关。

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