iNOS-dependent sweating and eNOS-dependent cutaneous vasodilation are evident in younger adults, but are diminished in older adults exercising in the heat
| Autor: | Imane Foudil-bey, Robert D. Meade, Lacy M. Alexander, Naoto Fujii, Pierre Boulay, Jeffrey C. Louie, Glen P. Kenny, Pegah Akbari |
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| Rok vydání: | 2016 |
| Předmět: |
Adult
Male medicine.medical_specialty Hot Temperature Nitric Oxide Synthase Type III Endothelium Physiology Nitric Oxide Synthase Type II Sweating Vasodilation 030204 cardiovascular system & hematology Nitric Oxide Endothelial NOS Nitric oxide Young Adult 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Enos Physiology (medical) Internal medicine Humans Medicine Exercise Aged Skin integumentary system biology business.industry Thermogenesis Articles Middle Aged biology.organism_classification Nitric oxide synthase medicine.anatomical_structure Endocrinology chemistry Anesthesia biology.protein Female business 030217 neurology & neurosurgery |
| Zdroj: | Journal of Applied Physiology. 120:318-327 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/japplphysiol.00714.2015 |
| Popis: | Nitric oxide synthase (NOS) contributes to sweating and cutaneous vasodilation during exercise in younger adults. We hypothesized that endothelial NOS (eNOS) and neuronal NOS (nNOS) mediate NOS-dependent sweating, whereas eNOS induces NOS-dependent cutaneous vasodilation in younger adults exercising in the heat. Further, aging may upregulate inducible NOS (iNOS), which may attenuate sweating and cutaneous vasodilator responses. We hypothesized that iNOS inhibition would augment sweating and cutaneous vasodilation in exercising older adults. Physically active younger ( n = 12, 23 ± 4 yr) and older ( n = 12, 60 ± 6 yr) adults performed two 30-min bouts of cycling at a fixed rate of metabolic heat production (400 W) in the heat (35°C). Sweat rate and cutaneous vascular conductance (CVC) were evaluated at four intradermal microdialysis sites with: 1) lactated Ringer (control), 2) nNOS inhibitor (nNOS-I, NPLA), 3) iNOS inhibitor (iNOS-I, 1400W), or 4) eNOS inhibitor (eNOS-I, LNAA). In younger adults during both exercise bouts, all inhibitors decreased sweating relative to control, albeit a lower sweat rate was observed at iNOS-I compared with eNOS-I and nNOS-I sites (all P < 0.05). CVC at the eNOS-I site was lower than control in younger adults throughout the intermittent exercise protocol (all P < 0.05). In older adults, there were no differences between control and iNOS-I sites for sweating and CVC during both exercise bouts (all P > 0.05). We show that iNOS and eNOS are the main contributors to NOS-dependent sweating and cutaneous vasodilation, respectively, in physically active younger adults exercising in the heat, and that iNOS inhibition does not alter sweating or cutaneous vasodilation in exercising physically active older adults. |
| Databáze: | OpenAIRE |
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