Diurnal variation in cutaneous vasodilator and vasoconstrictor systems during heat stress.
Diurnal variation in cutaneous vasodilator and vasoconstrictor systems during heat stress.
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DOI：
10.1152/ajpregu.2001.281.2.r591
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发表时间：
2001-08
期刊：
影响因子：
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通讯作者：
Ken Aoki;Ken Aoki;D. Stephens;John M. Johnson
中科院分区：
文献类型：
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作者：
Ken Aoki;Ken Aoki;D. Stephens;John M. Johnson
目前尚不清楚皮肤循环对热应激反应的昼夜变化是通过去甲肾上腺素能血管收缩系统还是非肾上腺素能主动血管舒张系统。我们在 0630（AM）和 1630（PM）对 8 名男性受试者进行了全身加热实验。通过激光多普勒血流测定法监测对照部位和用溴铵（BT）预处理以阻断去甲肾上腺素能血管收缩的部位的皮肤血流量。无创血压用于计算皮肤血管电导。 PM 对照组和 BT 治疗部位的皮肤血管舒张舌下温度 (T(or)) 阈值显着较高（均 P < 0.01），表明阈值的昼夜变化取决于活跃的血管舒张系统。仅在对照部位的 AM 中，皮肤血管电导率相对于 T(or) 的最大值的百分比的斜率显着较低。此外，在 AM 中，对照部位的斜率显着低于 BT 治疗部位的斜率 (P < 0.05)，表明皮肤血管舒张敏感性的昼夜变化取决于血管收缩系统功能。总体而言，热应激期间皮肤血流反射控制的昼夜变化涉及血管收缩系统和主动血管舒张系统。
It is not clear whether the diurnal variation in the cutaneous circulatory response to heat stress is via the noradrenergic vasoconstrictor system or the nonadrenergic active vasodilator system. We conducted whole body heating experiments in eight male subjects at 0630 (AM) and 1630 (PM). Skin blood flow was monitored by laser-Doppler flowmetry at control sites and at sites pretreated with bretylium (BT) to block noradrenergic vasoconstriction. Noninvasive blood pressure was used to calculate cutaneous vascular conductance. The sublingual temperature (T(or)) threshold for cutaneous vasodilation was significantly higher in PM at control and at BT-treated sites (both P < 0.01), suggesting the diurnal shift in threshold depends on the active vasodilator system. The slope of cutaneous vascular conductance as a percentage of its maximum with respect to T(or) was significantly lower in AM at control sites only. Also, in the AM, the slope at control sites was significantly lower than that at BT-treated sites (P < 0.05), suggesting that the diurnal change in the sensitivity of cutaneous vasodilation depends on vasoconstrictor system function. Overall, the diurnal variation in the reflex control of skin blood flow during heat stress involves both vasoconstrictor and active vasodilator systems.