Department of Exercise Sciences, Brigham Young University, Provo, Utah.
J Appl Physiol (1985). 2019 Oct 1;127(4):921-929. doi: 10.1152/japplphysiol.00308.2019. Epub 2019 Aug 29.
Cholinergic-activated sweating depends on an influx of Ca from extracellular fluid. It is thought that the opening of K channels on secretory epithelial cells facilitates Ca entry. We examined the hypothesis that tetraethylammonium (TEA)-sensitive K channels participate in sweat production. We used a pre-post experimental design and initiated cholinergic-mediated sweating with intradermal electrical stimulation, monitored local sweat rate (SR) with a small sweat capsule mounted on the skin, and delivered 50 mM TEA via intradermal microdialysis. Local SR was activated by intradermal stimulation frequencies of 0.2-64 Hz, and we generated a sigmoid-shaped stimulus-response curve by plotting the area under the SR-time curve versus log stimulus frequency. Peak local SR was reduced from 0.372 ± 0.331 to 0.226 ± 0.190 mg·min·cm ( = 0.0001) during application of 50 mM TEA, whereas the EC and Hill slopes were not altered. The global sigmoid-shaped stimulus-response curves for control and 50 mM TEA were significantly different ( < 0.0001), and the plateau region was significantly reduced ( = 0.0023) with the TEA treatment. The effect of TEA on peak local SR was similar in male and female subjects. However, we did note a small effect of sex on the shape of the stimulus-response curves during intradermal electrical stimulation. Overall, these data support the hypothesis that cholinergic control of sweat gland activity is modulated by the presence of TEA-sensitive K channels in human sweat gland epithelial cells. The contribution of various potassium channels to the process of cholinergic-mediated human eccrine sweat production is unclear. Using a novel model for cholinergic-mediated sweating in humans, we provide evidence that tetraethylammonium-sensitive K channels (K1.1 and K channels) contribute to eccrine sweat production.
胆碱能激活的出汗依赖于细胞外液中 Ca 的流入。据认为，分泌上皮细胞上 K 通道的开放有助于 Ca 进入。我们检验了这样一种假设，即四乙铵（TEA）敏感的 K 通道参与了汗液的产生。我们使用了预-后实验设计，通过皮内电刺激引发胆碱能介导的出汗，用贴在皮肤上的小汗液囊监测局部出汗率（SR），并通过皮内微透析给予 50 mM TEA。皮内刺激频率为 0.2-64 Hz 时，局部 SR 被激活，我们通过绘制 SR-时间曲线下面积与对数刺激频率的关系来生成一个 S 形刺激-反应曲线。在应用 50 mM TEA 时，局部峰值 SR 从 0.372 ± 0.331 减少到 0.226 ± 0.190 mg·min·cm（=0.0001），而 EC 和 Hill 斜率没有改变。在对照和 50 mM TEA 处理下，全局 S 形刺激-反应曲线有显著差异（<0.0001），且平台区在 TEA 处理后明显减少（=0.0023）。TEA 对男性和女性受试者局部峰值 SR 的影响相似。然而，我们确实注意到在皮内电刺激期间，性别对刺激-反应曲线的形状有很小的影响。总的来说，这些数据支持了这样一种假设，即 TEA 敏感的 K 通道在人类汗腺上皮细胞中存在，调节着汗腺活动的胆碱能控制。各种钾通道对胆碱能介导的人类外分泌汗腺分泌过程的贡献尚不清楚。我们使用一种新型的人类胆碱能介导的出汗模型，提供了证据表明，四乙铵敏感的 K 通道（K1.1 和 K 通道）有助于外分泌汗液的产生。
