Del Pozzi Andrew T, Hodges Gary J
Department of Pediatrics New York Medical College, Hawthorne, NY 10532, USA; Department of Physiology, New York Medical College, Hawthorne, NY 10532, USA; Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35468, USA.
Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35468, USA; Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.
Microvasc Res. 2015 Jan;97:47-54. doi: 10.1016/j.mvr.2014.09.006. Epub 2014 Oct 2.
The aim of this study is to determine the effect of repeated bouts of local skin heating on the roles of nitric oxide synthase (NOS) and sympathetic nerves in cutaneous vasodilatation. In 3 repeated-heating protocols skin blood flux of the forearm and leg was measured using laser-Doppler flowmetry and data are presented as cutaneous vascular conductance (CVC; flux/blood pressure). Local heating was performed from 33°C (thermoneutral) to 42°C at 0.5°C·10s(-1), allowed to cool passively for ~60-min, then reheated at the same rate. In protocol 1, CVC was measured in response to repeated heating. In protocol 2, NOS was inhibited with N(G)-nitro-l-arginine methyl ester (L-NAME) and in protocol 3, sympathetic nerve blockade was achieved with bretylium tosylate (BT), both infused via intradermal microdialysis. In protocol 1, there were no differences (P>0.05) in CVC at either the forearm (88±4 vs. 86±4%max) or the leg (97±4 vs. 96±6%max) between heating bouts. In protocol 2, no differences (P>0.05) in CVC were observed between heating bouts at L-NAME treated sites at either the forearm (55±3 vs. 51±4%max) or the leg (71±3 vs. 70±4%max) . In protocol 3, there were differences (P<0.001) between BT treated sites when comparing the first and second bouts of heating for both the forearm (75±3 vs. 88±4%max) and the leg (79±3 vs. 97±4%max). The effect of sympathetic blockade on CVC responses to local heating was abolished following repeated bouts of heating. Consequently, it is our suggestion that when examining mechanisms of skin blood flow control, investigators use single bouts of local heating.
本研究的目的是确定局部皮肤反复受热对一氧化氮合酶（NOS）和交感神经在皮肤血管舒张中作用的影响。在3种反复加热方案中，使用激光多普勒血流仪测量前臂和腿部的皮肤血流量，数据以皮肤血管传导率（CVC；血流量/血压）表示。局部加热从33°C（热中性）以0.5°C·10秒⁻¹的速度升至42°C，被动冷却约60分钟，然后以相同速度重新加热。在方案1中，测量反复加热时的CVC。在方案2中，用N⁃硝基⁃L⁃精氨酸甲酯（L⁃NAME）抑制NOS，在方案3中，用溴苄铵（BT）实现交感神经阻滞，二者均通过皮内微透析注入。在方案1中，前臂（88±4对86±4%最大值）或腿部（97±4对96±6%最大值）在各加热回合之间的CVC没有差异（P>0.05）。在方案2中，L⁃NAME处理部位在前臂（55±3对51±4%最大值）或腿部（71±3对70±4%最大值）的各加热回合之间未观察到CVC有差异（P>0.05）。在方案3中，比较前臂（75±3对88±4%最大值）和腿部（79±3对97±4%最大值）的第一轮和第二轮加热时，BT处理部位之间存在差异（P<0.001）。反复加热后，交感神经阻滞对局部加热引起的CVC反应的影响消失。因此，我们建议在研究皮肤血流控制机制时，研究人员采用单次局部加热。
