The role of baseline in the cutaneous vasoconstrictor responses during combined local and whole body cooling in humans.
The role of baseline in the cutaneous vasoconstrictor responses during combined local and whole body cooling in humans.
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基线在人体局部和全身联合冷却过程中皮肤血管收缩反应中的作用。
DOI：
10.1152/ajpheart.00815.2007
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Johnson,JohnM
中科院分区：
文献类型：
--
作者：
Hodges,GaryJ;Kosiba,WojciechA;Zhao,Kun;Alvarez,GuyE;Johnson,JohnM
先前的研究表明，局部冷却（LC）会减弱血管收缩剂对全身冷却（WBC）的反应。我们测试了这种衰减在多大程度上是由于LC后基线皮肤血流量减少造成的。在8名受试者中，使用激光多普勒血流仪（LDF）评估皮肤血流。皮肤血管传导（CVC）表示为LDF除以血压。受试者穿着水灌注服来控制白细胞。用微透析纤维、局部加热/冷却探针支架和激光多普勒探针制备四个前臂部位。3个部位局部温度从34℃降至28℃，CVC分别降至基线的45.9±3.9、42±3.9和44.5±4.8% （P< 0.05，各部位间P< 0.05）。在两个试验点，使用硝普钠（SNP）或异丙肾上腺素（Iso）将CVC恢复到预冷基线水平，CVC分别增加到基线的106.4±12.4和98.9±10.1%（与预冷相比P < 0.05）。除血流量测量区域外，全身皮肤温度从34℃降至31℃。与原始基线相比，CVC分别降低44.9±2.8（对照组）、11.3±2.4 （LC组）、29±3.7 （SNP组）和45.8±8.7% （Iso组）（P< 0.05）。LC位点和SNP位点的减少量低于对照和Iso位点（P< 0.05）；后两个部位的反应无显著差异（P < 0.05），提示CVC与LC的基线变化对白细胞反射性血管收缩反应的衰减很重要。
Previous work showed that local cooling (LC) attenuates the vasoconstrictor response to whole body cooling (WBC). We tested the extent to which this attenuation was due to the decreased baseline skin blood flow following LC. In eight subjects, skin blood flow was assessed using laser-Doppler flowmetry (LDF). Cutaneous vascular conductance (CVC) was expressed as LDF divided by blood pressure. Subjects were dressed in water-perfused suits to control WBC. Four forearm sites were prepared with microdialysis fibers, local heating/cooling probe holders, and laser-Doppler probes. Three sites were locally cooled from 34 to 28°C, reducing CVC to 45.9 ± 3.9, 42 ± 3.9, and 44.5 ± 4.8% of baseline (P< 0.05 vs. baseline;P> 0.05 among sites). At two sites, CVC was restored to precooling baseline levels with sodium nitroprusside (SNP) or isoproterenol (Iso), increasing CVC to 106.4 ± 12.4 and 98.9 ± 10.1% of baseline, respectively (P> 0.05 vs. precooling). Whole body skin temperature, apart from the area of blood flow measurement, was reduced from 34 to 31°C. Relative to the original baseline, CVC decreased (P< 0.05) by 44.9 ± 2.8 (control), 11.3 ± 2.4 (LC only), 29 ± 3.7 (SNP), and 45.8 ± 8.7% (Iso). The reductions at LC only and SNP sites were less than at control or Iso sites (P< 0.05); the responses at those latter sites were not different (P> 0.05), suggesting that the baseline change in CVC with LC is important in the attenuation of reflex vasoconstrictor responses to WBC.