Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.
Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.
Microvasc Res. 2018 Sep;119:22-28. doi: 10.1016/j.mvr.2018.04.002. Epub 2018 Apr 7.
To investigate cutaneous sensory nerve contribution to hyperaemia following chronic shear stress training.
Eleven males underwent a shear stress intervention (forearm occlusion 5 s, rest 10 s) for 30 min, 5 times·week for 6 weeks on one arm, the other was an untreated control. Skin blood flow was measured using laser-Doppler flowmetry, and sensory nerve function was assessed with and without blockade with EMLA cream in response to 3 levels of local heating (39, 42, and 44 °C) and post-occlusive reactive hyperaemia (PORH).
In response to local heating, EMLA treatment significantly delayed the onset of vasodilatation (p < 0.001), time-to-peak (p < 0.001), time to 39 °C (p < 0.02), time to 42 °C (p < 0.006), but not time to 44 °C (p > 0.2). EMLA treatment also increased time-to-peak for PORH (p ≤ 0.01). In the experimental limb after 6 weeks, both onset time and time to peak were shorter in response to local heating at the untreated and EMLA-treated sites (all p < 0.001). There were no changes in time-to-peak for PORH at the untreated and EMLA-treated sites (p ≥ 0.4); however, the peak PORH response was reduced with EMLA treatment (p ≤ 0.03). The 6-week intervention increased the peak PORH at the untreated sites (p < 0.001) but not at EMLA-treated (p > 0.05) sites. Comparing the control limb before and after 6 weeks, no differences in responses occurred at either the untreated skin sites (p ≥ 0.9) or the EMLA-treated sites (p ≥ 0.9).
Sensory nerve blockade attenuated the improvements in cutaneous vascular responses to thermal hyperaemia and PORH following chronic exposure to shear stress. These data demonstrate an important role for sensory nerve function in the initiation of vasodilatation to both PORH and thermal hyperaemia, in both the time to onset and the magnitude of vasodilatation.
研究慢性切变应力训练后皮肤感觉神经对充血的贡献。
11 名男性接受切变应力干预（前臂闭塞 5s，休息 10s），每周 5 次，每次 30min，共 6 周，其中一只手臂为未治疗对照。使用激光多普勒流量测定法测量皮肤血流量，并用 EMLA 乳膏阻滞感觉神经功能，以响应 3 个局部加热水平（39、42 和 44°C）和后闭塞性充血反应（PORH）。
在局部加热时，EMLA 治疗显著延迟了血管扩张的开始（p<0.001）、达到峰值的时间（p<0.001）、达到 39°C 的时间（p<0.02）、达到 42°C 的时间（p<0.006），但未达到 44°C 的时间（p>0.2）。EMLA 治疗还增加了 PORH 的达到峰值时间（p≤0.01）。在 6 周后的实验肢体中，未治疗和 EMLA 治疗部位的局部加热的起始时间和达到峰值时间均缩短（均 p<0.001）。未治疗和 EMLA 治疗部位的 PORH 达到峰值时间无变化（p≥0.4）；然而，EMLA 治疗降低了 PORH 的峰值（p≤0.03）。6 周的干预增加了未治疗部位的 PORH 峰值（p<0.001），但未治疗（p>0.05）部位的 EMLA 治疗则没有。比较 6 周前后的对照肢体，未治疗皮肤部位（p≥0.9）或 EMLA 治疗部位（p≥0.9）均未发生反应差异。
感觉神经阻滞减弱了慢性暴露于切变应力后皮肤血管对热充血和 PORH 的反应改善。这些数据表明，感觉神经功能在 PORH 和热充血的血管扩张开始时发挥重要作用，包括起始时间和血管扩张幅度。
