Prolonged residence of temperate natives in the tropics produces a suppression of sweating
Prolonged residence of temperate natives in the tropics produces a suppression of sweating
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DOI：
10.1007/s00424-006-0098-x
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发表时间：
2006-10-01
影响因子：
4.5
通讯作者：
Yang, Hun-Mo
中科院分区：
文献类型：
--
作者：
Bae, Jun-Sang;Lee, Jeong-Beom;Yang, Hun-Mo
热带原住民具有耐热性，因为他们能够有效地使用最少量的汗水来卸载内源性和外源性热量。另一方面，温和的本地人暴露在高温下会导致出汗过多，其中一部分因滴水而流失，因此无法蒸发。对于温带气候区的土著人，长期居住在热带地区是如何改变出汗的，目前还不清楚。本研究的目的是探讨外周出汗机制的可能变化。出汗反应离子电渗应用乙酰胆碱（ACh）之间的日本受试者永久居住在日本（日本居民，JRJ）或已在热带地区停留了2年或更长时间（热带居民日本，TRJ）进行了比较。通过ACh离子导入（10%，2mA，5分钟）进行的定量汗轴突反射试验，用于确定在[AXR（1）]和[AXR（2）] ACh离子导入期间直接激活的（ESTA）和轴突反射介导的出汗。JRJ组AXR（1）出汗反应时间比TRJ组短0.6min（P < 0.0001），且AXR（1）（P < 0.0004）、AXR（2）（P < 0.0001）和AXR（2）（P < 0.0001）出汗反应均大于TRJ组。AXR和DIR出汗量（P < 0.0001）呈负相关，出汗开始时间（P < 0.0001）与热带居住时间（2至13年）正相关。观察到的衰减出汗TRJ表明，温带原住民可能会获得耐热性与改善出汗经济类似的热带原住民长期居住在热带地区。
Tropical natives possess heat tolerance due to the ability to off-load endogenous and exogenous heat efficiently using a minimum amount of sweat. On the other hand, exposure of temperate natives to heat results in exaggerated production of sweat, of which part is lost by dripping and, thus, not available for evaporation. How sweating is modified in natives of temperate climate zones by prolonged residence in the tropics is not well-understood. The aim of this study was to investigate possible changes in the peripheral sweating mechanisms. Sweating responses to iontophoretically applied acetylcholine (ACh) were compared between Japanese subjects having either permanently resided in Japan (Japan resident Japanese, JRJ) or having stayed in the tropics for 2 years or longer (Tropics resident Japanese, TRJ). Quantitative sudomotor axon reflex tests by iontophoresis of ACh (10%, 2 mA for 5 min) were applied to determine directly activated (DIR) and axon reflex-mediated sweating during [AXR(l)] and after [AXR(2)] ACh iontophoresis. The sweat onset time of AXR(l) was 0.6 min shorter in JRJ than in TRJ (P < 0.0001), and AXR(l) (P < 0.0004), AXR(2) (P < 0.0001), and DIR (P < 0.0001) sweating responses were larger in JRJ than in TRJ. AXR and DIR sweating volumes (P < 0.0001) were negatively correlated, and sweat onset times (P < 0.0001) were positively correlated with the duration of residence in the tropics (2 to 13 years). The observed attenuation of sweating in TRJ suggests that temperate natives may acquire heat tolerance with improved sweating economy similar to tropical natives after prolonged residence in the tropics.