Plasma hyperosmolality attenuates skin sympathetic nerve activity during passive heat stress in humans
Gagnon D, Romero SA, Ngo H, Poh PY, Crandall CG
The Journal of physiology · 27 citations
How it was studied
- Design
- Controlled clinical trial (classified by our AI screen)
- Studied in
- People
- Main outcome
- Health markers and function
Who paid for it
- Funding
- Independent funding
- Government
- Natural Sciences and Engineering Research Council of Canada
- Government
- National Institute of General Medical Sciences
- Government
- NIGMS NIH HHS
- Grants
- National Institute of General Medical Sciences (GM068865); National Institute of General Medical Sciences (R01GM068865)
Based on 3 listed funder(s).
Publication
- Published
- 2015-11-03 · J Physiol · vol. 594 · issue 2 · pp. 497–506
- Publisher
- Wiley
- Cited
- 31 citations · more than 88% of similar papers · 2.4× the field average
- References
- 48 works
- Access
- Open access (repository copy)
- Research areas
- Thermoregulation and physiological responses · Thermal Regulation in Medicine · Sympathectomy and Hyperhidrosis Treatments
- Keywords
- Saline, Renal physiology, Axon reflex, Vasodilation, Thermoregulation, Microdialysis, Osmotic concentration, Chemistry, Medicine, Endocrinology, Internal medicine, Anesthesia, Kidney, Central nervous system
- MeSH
- sympathetic nervous system, skin, humans, body temperature regulation, heat-shock response, plasma volume, osmolar concentration, adult, middle aged, female, male
5 authors
From US
- Daniel GagnonTexas Health Dallas; Institute for Exercise and Environmental Medicine; The University of Texas Southwestern Medical Center
- Steven A. RomeroTexas Health Dallas; Institute for Exercise and Environmental Medicine; The University of Texas Southwestern Medical Center
- Hai T. NgoTexas Health Dallas; Institute for Exercise and Environmental Medicine; The University of Texas Southwestern Medical Center
- Paula Y. S. PohTexas Health Dallas; Institute for Exercise and Environmental Medicine; The University of Texas Southwestern Medical Center
- Craig G. Crandall · correspondingTexas Health Dallas; Institute for Exercise and Environmental Medicine; The University of Texas Southwestern Medical Center
Abstract
Key points
Plasma hyperosmolality delays the onset for sweat production and cutaneous vasodilatation during heat stress in humans; however, the mechanism by which hyperosmolality exerts this effect remains unknown. This study examined if plasma hyperosmolality exerts a central and/or peripheral modulation of thermoregulatory function in humans. The main findings are that plasma hyperosmolality delays the increase in skin sympathetic nerve activity during whole-body passive heat stress in humans. In contrast, local intradermal infusion of hyperosmotic saline did not affect sweating or cutaneous vasodilatation. These results suggest that plasma hyperosmolality delays the onset threshold for sweating and cutaneous vasodilatation by inhibiting efferent thermoregulatory activity in humans.
Abstract
In humans, plasma hyperosmolality delays the onset of sweating and cutaneous vasodilatation during heat stress. However, it remains unknown if hyperosmolality exerts this effect through a central (i.e. CNS) and/or peripheral (i.e. effector organ) modulation of thermoregulatory activity. We examined if intravenous infusion of hyperosmotic saline affects skin sympathetic nerve activity (SSNA) during whole-body passive heating in healthy humans. Furthermore, we examined if local intradermal infusion of hyperosmotic saline affects sweating and cutaneous vasodilatation during passive heating. Following intravenous infusion of either 0.9% (ISO) or 3.0% (HYPER) NaCl saline, 12 subjects were passively heated until core temperature increased by ∼0.6°C. During each condition, sweating and cutaneous vascular conductance were measured over two intradermal microdialysis probes, one perfused with ISO saline and the other with HYPER saline. Intravenous infusion of HYPER saline increased plasma osmolality (294 ± 3 to 316 ± 5 mOsm kg(-1) H2O, P ≤ 0.01), which remained greater than ISO throughout heating. Plasma hyperosmolality delayed the mean body temperature onset of sweating (+1.24 ± 0.18 vs. +1.60 ± 0.18°C, P ≤ 0.01) and cutaneous vasodilatation (+1.15 ± 0.18 vs. +1.53 ± 0.22°C, P ≤ 0.01), and attenuated the increase in SSNA during heating (+147 ± 178 vs. +427 ± 281%, P ≤ 0.01). Intradermal infusion of HYPER saline increased baseline cutaneous vascular conductance (P ≤ 0.01), which did not increase further during the subsequent heating period (P = 0.11). In contrast, intradermal infusion of HYPER saline did not affect sweating (P = 0.99). These results provide direct evidence that plasma hyperosmolality exerts a central modulatory effect governing efferent thermoregulatory activity in humans.
Abstract via Europe PMC. Copyright remains with the authors or publisher.
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