TEA-sensitive K + channels and human eccrine sweat gland output

• Published in: Journal of applied physiology (1985) Vol. 127; no. 4; pp. 921 - 929
• Main Authors: Mack, Gary W., Smith, Benjamin S., Rowland, Benjamin
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.10.2019
• Subjects: Calcium (extracellular); Calcium influx; Calcium ions; Channels; Cholinergics; Design of experiments; Electrical stimuli; Epithelial cells; Experimental design; Hypotheses; Microdialysis; Potassium; Skin; Stimulation; Sweat; Sweat gland; Sweating; Tetraethylammonium; sweat secretion; epithelial transport; thermoregulation; sympathetic cholinergic nerve
• ISSN: 8750-7587; 1522-1601; 1522-1601
• DOI: 10.1152/japplphysiol.00308.2019

Cholinergic-activated sweating depends on an influx of Ca 2+ from extracellular fluid. It is thought that the opening of K + channels on secretory epithelial cells facilitates Ca 2+ 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 10 stimulus frequency. Peak local SR was reduced from 0.372 ± 0.331 to 0.226 ± 0.190 mg·min −1 ·cm −2 ( P = 0.0001) during application of 50 mM TEA, whereas the EC 50 and Hill slopes were not altered. The global sigmoid-shaped stimulus-response curves for control and 50 mM TEA were significantly different ( P < 0.0001), and the plateau region was significantly reduced ( P = 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. NEW & NOTEWORTHY 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 (K Ca 1.1 and K v channels) contribute to eccrine sweat production.