The effect of endothelin A and B receptor blockade on cutaneous vascular and sweating responses in young men during and following exercise in the heat

• Published in: Journal of applied physiology (1985) 2016-12, Vol.121 (6), p.1263-1271
• Main Authors: Fujii, Naoto, Singh, Maya S, Halili, Lyra, Louie, Jeffrey C, Kenny, Glen P
• Format: Article
• Language: English
• Subjects: Adult; Endothelin A Receptor Antagonists - pharmacology; Endothelin B Receptor Antagonists - pharmacology; Exercise - physiology; Hot Temperature; Humans; Male; Receptor, Endothelin A - metabolism; Receptor, Endothelin B - metabolism; Skin - blood supply; Skin - drug effects; Skin - metabolism; Skin - physiopathology; Sweating - drug effects; Sweating - physiology; Vasodilation - drug effects; Vasodilation - physiology; Young Adult
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00679.2016

During exercise, cutaneous vasodilation and sweating responses occur, whereas these responses rapidly decrease during postexercise recovery. We hypothesized that the activation of endothelin A (ET ) receptors, but not endothelin B (ET ) receptors, attenuate cutaneous vasodilation during high-intensity exercise and contribute to the subsequent postexercise suppression of cutaneous vasodilation. We also hypothesized that both receptors increase sweating during and following high-intensity exercise. Eleven men (24 ± 4 yr) performed an intermittent cycling protocol consisting of two 30-min bouts of moderate- (40% V̇o ) and high-intensity (75% V̇o ) exercise in the heat (35°C), each separated by a 20- and 40-min recovery period, respectively. Cutaneous vascular conductance (CVC) and sweat rate were evaluated at four intradermal microdialysis skin sites: 1) lactated Ringer (control), 2) 500 nM BQ123 (a selective ET receptor blocker), 3) 300 nM BQ788 (a selective ET receptor blocker), or 4) a combination of BQ123 + BQ788. There were no between-site differences in CVC during each exercise bout (all P > 0.05); however, CVC following high-intensity exercise was greater at BQ123 (56 ± 9%max) and BQ123 + BQ788 (55 ± 14%max) sites relative to the control site (43 ± 12%max) (all P ≤ 0.05). Sweat rate did not differ between sites throughout the protocol (all P > 0.05). We show that neither ET nor ET receptors modulate cutaneous vasodilation and sweating responses during and following moderate- and high-intensity exercise in the heat, with the exception that ET receptors may partly contribute to the suppression of cutaneous vasodilation following high-intensity exercise.