Witter Trevor, Tzeng Yu-Chieh, O'Donnell Terry, Kusel Jessica, Walker Bridget, Berry Mary, Taylor Chloe E
Wellington Medical Technology Group, Centre for Translational Physiology, University of OtagoWellington, New Zealand.
School of Science and Health, Western Sydney UniversitySydney, NSW, Australia.
Front Neurosci. 2017 Aug 15;11:457. doi: 10.3389/fnins.2017.00457. eCollection 2017.
Maintenance of adequate cerebral perfusion during normal physiological challenges requires integration between cerebral blood flow (CBF) and systemic blood pressure control mechanisms. Previous studies have shown that cardiac baroreflex sensitivity (BRS) is inversely related to some measures of cerebral autoregulation. However, interactions between the sympathetic arterial baroreflex and cerebral perfusion control mechanisms have not been explored. To determine the nature and magnitude of these interactions we measured R-R interval, blood pressure, CBF velocity, and muscle sympathetic nerve activity (MSNA) in 11 healthy young males. Sympathetic BRS was estimated using modified Oxford method as the relationship between beat-to-beat diastolic blood pressure (DBP) and MSNA. Integrated control of CBF was quantified using transfer function analysis (TFA) metrics derived during rest and Tieck's autoregulatory index following bilateral thigh cuff deflation. Sympathetic BRS during modified Oxford trials was significantly related to autoregulatory index ( = 0.64, = 0.03). Sympathetic BRS during spontaneous baseline was significantly related to transfer function gain ( = -0.74, = 0.01). A more negative value for sympathetic BRS indicates more effective arterial baroreflex regulation, and a lower transfer function gain reflects greater cerebral autoregulation. Therefore, these findings indicate that males with attenuated CBF regulation have greater sympathetic BRS (and vice versa), consistent with compensatory interactions between blood pressure and cerebral perfusion control mechanisms.
在正常生理应激期间维持充足的脑灌注需要脑血流量（CBF）和全身血压控制机制之间的整合。先前的研究表明，心脏压力反射敏感性（BRS）与脑自动调节的某些指标呈负相关。然而，交感神经动脉压力反射与脑灌注控制机制之间的相互作用尚未得到探讨。为了确定这些相互作用的性质和程度，我们测量了11名健康年轻男性的R-R间期、血压、CBF速度和肌肉交感神经活动（MSNA）。使用改良牛津法估计交感神经BRS，即逐搏舒张压（DBP）与MSNA之间的关系。使用在休息期间得出的传递函数分析（TFA）指标和双侧大腿袖带放气后的蒂克自动调节指数对CBF的综合控制进行量化。改良牛津试验期间的交感神经BRS与自动调节指数显著相关（r = 0.64，P = 0.03）。自发基线期间的交感神经BRS与传递函数增益显著相关（r = -0.74，P = 0.01）。交感神经BRS的负值越大表明动脉压力反射调节越有效，传递函数增益越低反映脑自动调节越强。因此，这些发现表明，CBF调节减弱的男性具有更高的交感神经BRS（反之亦然），这与血压和脑灌注控制机制之间的代偿性相互作用一致。
