Autoregulation in the ocular and cerebral arteries during the cold pressor test and handgrip exercise
Autoregulation in the ocular and cerebral arteries during the cold pressor test and handgrip exercise
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DOI：
10.1007/s00421-011-2016-y
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发表时间：
2012-02-01
影响因子：
3
通讯作者：
Hayashi, Naoyuki
中科院分区：
文献类型：
--
作者：
Ikemura, Tsukasa;Someya, Nami;Hayashi, Naoyuki
本研究的目的是确定自动调节是否在眼血管和脑血管中发挥类似的作用，这两个血管都是颈内动脉的分支。在静息2 min、静态握力运动（HG）和冷压试验（CPT）下，测定了11例受试者的眼血流速度、脑血流速度和血压。激光散斑血流法测量时，获得上、下颞视网膜小动脉（分别为STRA和ITRA）以及视网膜和脉络膜血管（RCV）的血流速度数据，时间为4 s。经颅多普勒超声测量大脑中动脉平均血流速度（MCAVmean）。通过血流量除以平均动脉压计算各血管的传导指数（CI）。在CPT期间，RCV的血流速度比静息基线水平增加了19 +/- 9% (P < 0.05)，而STRA、ITRA和MCAVmean的血流速度没有增加。MCA的CI降低。HG期间RCV血流速度、ITRA血流速度和MCAVmean分别增加了8 +/- 1、9 +/- 3和11 +/- 4% （P < 0.05）。相反，STRA血流量保持不变。HG没有显著改变任何测量血管的CI。这些结果表明，脑血流速度在CPT期间得到维持，但在CPT和HG期间，RCV的自动调节作用不佳。
The aim of this study was to determine whether autoregulation exerts similar effects in the ocular and cerebral vessels, which are both branches of the internal carotid artery. Ocular blood flow velocities, cerebral blood flow velocity and blood pressure were measured in 11 subjects during a 2-min resting period, static handgrip exercise (HG) and a cold pressor test (CPT). Blood velocity data for the superior and inferior temporal retinal arterioles (STRA and ITRA, respectively) and the retinal and choroidal vasculature (RCV) were obtained for 4 s during the measurement using laser speckle flowmetry. Mean blood flow velocity in the middle cerebral artery (MCAVmean) was measured by transcranial Doppler ultrasound. The conductance index (CI) of each vessel was calculated by dividing blood flow by mean arterial pressure. Blood flow velocity in the RCV increased by 19 +/- 9% from resting baseline level during the CPT (P < 0.05), while blood flow in the STRA, ITRA and MCAVmean did not. The CI of the MCA decreased. The RCV blood flow velocity, ITRA blood flow and MCAVmean increased by 8 +/- 1, 9 +/- 3 and 11 +/- 4%, respectively, during the HG (P < 0.05). Conversely, STRA blood flow remained unchanged. The HG did not significantly change the CI in any of the vessels measured. These findings suggest that cerebral blood flow velocity was maintained during the CPT, but autoregulation does not work well in the RCV during the CPT and HG.