1
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Martin LS, Josset-Lamaugarny A, El Jammal T, Ducreux S, Chevalier FP, Fromy B. Aging is associated with impaired triggering of TRPV3-mediated cutaneous vasodilation: a crucial process for local heat exposure. GeroScience 2024; 46:3567-3580. [PMID: 37855862 PMCID: PMC11226586 DOI: 10.1007/s11357-023-00981-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 10/09/2023] [Indexed: 10/20/2023] Open
Abstract
Sensing temperature is vitally important to adapt our body to environmental changes. Local warm detection is required to initiate regulation of cutaneous blood flow, which is part of the peripheral thermoregulatory mechanisms, and thus avoid damage to surrounding tissues. The mechanisms mediating cutaneous vasodilation during local heat stress are impaired with aging. However, the impact of aging on the ability of the skin to detect subtle thermal changes is unknown. Among heat-activated cation channels, transient receptor potential vanilloid 3 (TRPV3) is a thermo-sensor predominantly expressed on keratinocytes and involved in local vascular thermoregulatory mechanisms of the skin in young mice. In the present study, using a murine in vivo model of local heat exposure of the skin, we showed that heat-induced vasodilation was reduced in old mice associated with reduced expression of TRPV3 channels. We also found a decrease in expression and activity of TRPV3 channel, as well as reduced TRPV3-dependent adenosine tri-phosphate release in human primary keratinocytes from old donors. This study shows that aging alters the epidermal TRPV3 channels, which might delay the detection of changes in skin temperature, thereby limiting the mechanisms triggered for local vascular thermoregulation in the old skin.
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Affiliation(s)
- Lisa S Martin
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France
| | - Audrey Josset-Lamaugarny
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France
| | - Thomas El Jammal
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France
- Department of Internal Medicine, University Hospital Lyon Croix-Rousse, Claude Bernard University Lyon 1, Lyon, France
| | - Sylvie Ducreux
- CarMeN Laboratory, INSERM, INRA, INSA Lyon, Claude Bernard University Lyon 1, 69500, Bron, France
| | - Fabien P Chevalier
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France
| | - Bérengère Fromy
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France.
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France.
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2
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Zarębska EA, Kusy K, Korman P, Słomińska EM, Zieliński J. Exercise-induced changes in lower limbs skin temperature against plasma ATP among individuals with various type and level of physical activity. J Therm Biol 2024; 122:103877. [PMID: 38850622 DOI: 10.1016/j.jtherbio.2024.103877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/10/2024]
Abstract
The objective of the study was to examine the lower limbs skin temperature (TSK) changes in response to exhaustive whole-body exercise in trained individuals in reference to changes in plasma adenosine triphosphate (ATP). Eighteen trained participants from distinct sport type ‒ endurance (25.2 ± 4.9 yr) and speed-power (25.8 ± 3.1 yr), and 9 controls (24,9 ± 4,3 yr) ‒ were examined. Lower limbs TSK and plasma ATP measures were applied in parallel in response to incremental treadmill test and during 30-min recovery period. Plasma ATP kinetics were inversely associated to changes in TSK. The first significant decrease in TSK (76-89% of V˙ O2MAX) occurred shortly before a significant plasma ATP increase (86-97% of V˙ O2MAX). During recovery, TSK increased, reaching pre-exercise values (before exercise vs. after 30-min recovery: 31.6 ± 0.4 °C vs. 32.0 ± 0.8 °C, p = 0.855 in endurance; 32.4 ± 0.5 °C vs. 32.9 ± 0.5 °C, p = 0.061 in speed-power; 31.9 ± 0.7 °C vs. 32.4 ± 0.8 °C, p = 0.222 in controls). Plasma ATP concentration did not returned to pre-exercise values in well trained participants (before exercise vs. after 30-min recovery: 699 ± 57 nmol l-1 vs. 854 ± 31 nmol l-1, p < 0.001, η2 = 0.961 and 812 ± 35 nmol l-1 vs. 975 ± 55 nmol l-1, p < 0.001, η2 = 0.974 in endurance and speed-power, respectively), unlike in controls (651 ± 40 nmol l-1 vs. 687 ± 61 nmol·l-1, p = 0.58, η2 = 0.918). The magnitude of TSK and plasma ATP response differed between the groups (p < 0.001, η2 = 0.410 for TSK; p < 0.001, η2 = 0.833 for plasma ATP). We conclude that lower limbs TSK change indirectly corresponds to the reverse course of plasma ATP during incremental exercise and the magnitude of the response depends on the level of physical activity and the associated to it long-term metabolic adaptation.
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Affiliation(s)
- Ewa A Zarębska
- Department of Athletics, Strength and Conditioning, Poznan University of Physical Education, 61-871, Poznan, Poland.
| | - Krzysztof Kusy
- Department of Athletics, Strength and Conditioning, Poznan University of Physical Education, 61-871, Poznan, Poland.
| | - Paweł Korman
- Department of Physical Therapy and Sports Recovery, Poznan University of Physical Education, 61-871, Poznan, Poland.
| | - Ewa M Słomińska
- Department of Biochemistry, Medical University of Gdansk, 80-211, Gdansk, Poland.
| | - Jacek Zieliński
- Department of Athletics, Strength and Conditioning, Poznan University of Physical Education, 61-871, Poznan, Poland.
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3
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Terwoord JD, Racine ML, Hearon CM, Luckasen GJ, Dinenno FA. ATP and acetylcholine interact to modulate vascular tone and α 1-adrenergic vasoconstriction in humans. J Appl Physiol (1985) 2021; 131:566-574. [PMID: 34166116 DOI: 10.1152/japplphysiol.00205.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vascular endothelium senses and integrates numerous inputs to regulate vascular tone. Recent evidence reveals complex signal processing within the endothelium, yet little is known about how endothelium-dependent stimuli interact to regulate blood flow. We tested the hypothesis that combined stimulation of the endothelium with adenosine triphosphate (ATP) and acetylcholine (ACh) elicits greater vasodilation and attenuates α1-adrenergic vasoconstriction compared with combination of ATP or ACh with the endothelium-independent dilator sodium nitroprusside (SNP). We assessed forearm vascular conductance (FVC) in young adults (6 women, 7 men) during local intra-arterial infusion of ATP, ACh, or SNP alone and in the following combinations: ATP + ACh, SNP + ACh, and ATP + SNP, wherein the second dilator was coinfused after attaining steady state with the first dilator. By design, each dilator evoked a similar response when infused separately (ΔFVC, ATP: 48 ± 4; ACh: 57 ± 6; SNP: 53 ± 6 mL·min-1·100 mmHg-1; P ≥ 0.62). Combined infusion of the endothelium-dependent dilators evoked greater vasodilation than combination of either dilator with SNP (ΔFVC from first dilator, ATP + ACh: 45 ± 9 vs. SNP + ACh: 18 ± 7 and ATP + SNP: 26 ± 4 mL·min-1·100 mmHg-1, P < 0.05). Phenylephrine was subsequently infused to evaluate α1-adrenergic vasoconstriction. Phenylephrine elicited less vasoconstriction during infusion of ATP or ACh versus SNP (ΔFVC, -25 ± 3 and -29 ± 4 vs. -48 ± 3%; P < 0.05). The vasoconstrictor response to phenylephrine was further diminished during combined infusion of ATP + ACh (-13 ± 3%; P < 0.05 vs. ATP or ACh alone) and was less than that observed when either dilator was combined with SNP (SNP + ACh: -26 ± 3%; ATP + SNP: -31 ± 4%; both P < 0.05 vs. ATP + ACh). We conclude that endothelium-dependent agonists interact to elicit vasodilation and limit α1-adrenergic vasoconstriction in humans.NEW & NOTEWORTHY The results of this study highlight the vascular endothelium as a critical site for integration of vasomotor signals in humans. To our knowledge, this is the first study to demonstrate that combined stimulation of the endothelium with ATP and ACh results in enhanced vasodilation compared with combination of either ATP or ACh with an endothelium-independent dilator. Furthermore, we show that ATP and ACh interact to modulate α1-adrenergic vasoconstriction in human skeletal muscle in vivo.
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Affiliation(s)
- Janée D Terwoord
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, Colorado
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
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4
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Fujii N, McGarr GW, Ghassa R, Schmidt MD, McCormick JJ, Nishiyasu T, Kenny GP. Sex-differences in cholinergic, nicotinic, and β-adrenergic cutaneous vasodilation: Roles of nitric oxide synthase, cyclooxygenase, and K + channels. Microvasc Res 2020; 131:104030. [PMID: 32531353 DOI: 10.1016/j.mvr.2020.104030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 05/22/2020] [Accepted: 06/05/2020] [Indexed: 12/15/2022]
Abstract
Previous studies indicate that sex-related differences exist in the regulation of cutaneous vasodilation, however, the mechanisms remain unresolved. We assessed if sex-differences in young adults exist for cholinergic, nicotinic, and β-adrenergic cutaneous vasodilation with a focus on nitric oxide synthase (NOS), cyclooxygenase (COX), and K+ channel mechanisms. In twelve young men and thirteen young women, four intradermal forearm skin sites were perfused with the following: 1) lactated Ringer's solution (control), 2) 10 mM Nω-nitro-l-arginine, a non-selective NOS inhibitor, 3) 10 mM ketorolac, a non-selective COX inhibitor, or 4) 50 mM BaCl2, a nonspecific K+ channel blocker. At all four sites, cutaneous vasodilation was induced by 1) 10 mM nicotine, a nicotinic receptor agonist, 2) 100 μM isoproterenol, a nonselective β-adrenergic receptor agonist, and 3) 2 mM and 2000 mM acetylcholine, an acetylcholine receptor agonist. Nicotine and isoproterenol were administered for 3 min, whereas each acetylcholine dose was administered for 25 min. Regardless of treatment site, cutaneous vasodilation in response to nicotine and a high dose of acetylcholine (2000 mM) were lower in women than men. By contrast, isoproterenol induced cutaneous vasodilation was greater in women vs. men. Irrespective of sex, NOS inhibition or K+ channel blockade attenuated isoproterenol-mediated cutaneous vasodilation, whereas K+ channel blockade decreased nicotine-induced cutaneous vasodilation. Taken together, our findings indicate that while the mechanisms underlying cutaneous vasodilation are comparable between young men and women, sex-related differences in the magnitude of cutaneous vasodilation do exist and this response differs as a function of the receptor agonist.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.
| | - Gregory W McGarr
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Reem Ghassa
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Madison D Schmidt
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - James J McCormick
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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5
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Fujii N, McGarr GW, McNeely BD, Ichinose M, Nishiyasu T, Kenny GP. K Ca and K V channels modulate the venoarteriolar reflex in non-glabrous human skin with no roles of K ATP channels, NOS, and COX. Eur J Pharmacol 2019; 866:172828. [PMID: 31790651 DOI: 10.1016/j.ejphar.2019.172828] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 11/23/2019] [Accepted: 11/29/2019] [Indexed: 11/25/2022]
Abstract
The venoarteriolar reflex is a local mechanism that induces vasoconstriction during venous congestion in various tissues, including skin. This response is thought to play a critical role in minimizing capillary damage or edema resulting from overperfusion, though factors that modulate this response remain largely unknown. Here, we hypothesized that nitric oxide synthase (NOS), cyclooxygenase (COX), and Ca2+-activated, ATP-sensitive, and voltage-gated K+ channels (KCa, KATP, and KV channels, respectively) modulate the venoarteriolar reflex in human skin. Cutaneous blood flow (laser-Doppler flowmetry) was monitored during a 3-min pre-occlusion baseline and following a 3-min venous occlusion of 45 mmHg, the latter maneuver was used to induce the venoarteriolar reflex. The venoarteriolar reflex was assessed at the following forearm skin sites: Experiment 1 (n = 11): 1) lactated Ringer solution (Control), 2) 10 mM Nω-nitro-L-arginine (NOS inhibitor), 3) 10 mM ketorolac (COX inhibitor), and 4) combined NOS + COX inhibition; Experiment 2 (n = 15): 1) lactated Ringer solution (Control), 2) 50 mM tetraethylammonium (KCa channel blocker), 3) 5 mM glybenclamide (KATP channel blocker), and 4) 10 mM 4-aminopyridine (KV channel blocker). Separate and combined NOS and COX inhibition as well as KATP channel blocker had no effect on venoarteriolar reflex. Conversely, venoarteriolar reflex was attenuated by KCa channel blockade (36-38%) and augmented by KV channel blockade (38-55%). We showed that KCa and KV channels modulate the venoarteriolar reflex with minimum roles of NOS, COX, and KATP channels in human non-glabrous forearm skin in vivo. Thus, cutaneous venoarteriolar reflex changes could reflect altered K+ channel function.
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Affiliation(s)
- Naoto Fujii
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan.
| | - Gregory W McGarr
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Brendan D McNeely
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Masashi Ichinose
- Human Integrative Physiology Laboratory, School of Business Administration, Meiji University, Tokyo, Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
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6
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Kamijo YI, Okazaki K, Ikegawa S, Okada Y, Nose H. Rapid saline infusion and/or drinking enhance skin sympathetic nerve activity components reduced by hypovolaemia and hyperosmolality in hyperthermia. J Physiol 2019; 596:5443-5459. [PMID: 30242837 DOI: 10.1113/jp276633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 09/05/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS In hyperthermia, plasma hyperosmolality suppresses both cutaneous vasodilatation and sweating responses and this suppression is removed by oropharyngeal stimulation such as drinking. Hypovolaemia suppresses only cutaneous vasodilatation, which is enhanced by rapid infusion in hyperthermia. Our recent studies suggested that skin sympathetic nerve activity (SSNA) involves components synchronized and non-synchronized with the cardiac cycle, which are associated with an active vasodilator and a sudomotor, respectively. In the present study, plasma hyperosmolality suppressed both components; drinking removed the hyperosmolality-induced suppressions, simultaneously with increases in cutaneous vasodilatation and sweating, while not altering plasma volume and osmolality. Furthermore, a rapid saline infusion increased the synchronized component and cutaneous vasodilatation in hypovolaemic and hyperthermic humans. The results support our idea that SSNA involves an active cutaneous vasodilator and a sudomotor, and that a site where osmolality signals are projected to control thermoregulation is located more superior than the medulla where signals from baroreceptors are projected. ABSTRACT We reported that skin sympathetic nerve activity (SSNA) involved components synchronized and non-synchronized with the cardiac cycle; both components increased in hyperthermia and our results suggested that the components are associated with an active vasodilator and a sudomotor, respectively. In the present study, we examined whether the increases in the components in hyperthermia would be suppressed by plasma hyperosmolality simultaneously with suppression of cutaneous vasodilatation and sweating and whether this suppression was released by oropharyngeal stimulation (drinking). Also, effects of a rapid saline infusion on both components and responses of cutaneous vasodilatation and sweating were tested in hypovolaemic and hyperthermic subjects. We found that (1) plasma hyperosmolality suppressed both components in hyperthermia, (2) the suppression was released by drinking 200 mL of water simultaneously with enhanced cutaneous vasodilatation and sweating responses, and (3) a rapid infusion at 1.0 and 0.2 ml min-1 kg-1 for the first 10 min and the following 20 min, respectively, increased the synchronized component and cutaneous vasodilatation in diuretic-induced hypovolaemia greater than those in a time control; at 0.1 ml min-1 kg-1 for 30 min no greater increases in the non-synchronized component and sweating responses were observed during rapid infusion than in the time control. The results support the idea that SSNA involves components synchronized and non-synchronized with the cardiac cycle, associated with the active cutaneous vasodilator and sudomotor, and a site of osmolality-induced modulation for thermoregulation is located superior to the medulla where signals from baroreceptors are projected.
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Affiliation(s)
- Yoshi-Ichiro Kamijo
- Department of Sports Medical Sciences, Shinshu University Graduate School of Medicine, Matsumoto, Japan.,Department of Advances Medicine for Health Promotion, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto, Japan.,Department of Rehabilitation Medicine, Wakayama Medical University, Wakayama, Japan
| | - Kazunobu Okazaki
- Department of Sports Medical Sciences, Shinshu University Graduate School of Medicine, Matsumoto, Japan.,Department of Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, and Research Center for Urban Health and Sports, Osaka City University, Osaka, Japan
| | - Shigeki Ikegawa
- Department of Sports Medical Sciences, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Yoshiyuki Okada
- Department of Sports Medical Sciences, Shinshu University Graduate School of Medicine, Matsumoto, Japan.,Department of Special Care Dentistry, Hiroshima University, Hiroshima, Japan
| | - Hiroshi Nose
- Department of Sports Medical Sciences, Shinshu University Graduate School of Medicine, Matsumoto, Japan.,Department of Advances Medicine for Health Promotion, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto, Japan
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7
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Fujii N, Amano T, Kenny GP, Honda Y, Kondo N, Nishiyasu T. Nicotinic receptors modulate skin perfusion during normothermia, and have a limited role in skin vasodilatation and sweating during hyperthermia. Exp Physiol 2019; 104:1808-1818. [DOI: 10.1113/ep088072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 10/11/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Naoto Fujii
- Faculty of Health and Sport SciencesUniversity of Tsukuba Tsukuba Japan
| | - Tatsuro Amano
- Laboratory for Exercise and Environmental PhysiologyFaculty of EducationNiigata University Niigata Japan
| | - Glen P. Kenny
- Human and Environmental Physiology Research UnitUniversity of Ottawa Ottawa Canada
| | - Yasushi Honda
- Faculty of Health and Sport SciencesUniversity of Tsukuba Tsukuba Japan
| | - Narihiko Kondo
- Laboratory for Applied Human PhysiologyGraduate School of Human Development and EnvironmentKobe University Kobe Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport SciencesUniversity of Tsukuba Tsukuba Japan
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8
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Fujii N, McGarr GW, Sigal RJ, Boulay P, Nishiyasu T, Kenny GP. Ageing augments nicotinic and adenosine triphosphate-induced, but not muscarinic, cutaneous vasodilatation in women. Exp Physiol 2019; 104:1801-1807. [PMID: 31602716 DOI: 10.1113/ep088144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 10/08/2019] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does ageing augment muscarinic, nicotinic and/or ATP-mediated cutaneous vasodilatation in women? What is the main finding and its importance? Ageing augments nicotinic and ATP-induced, but not muscarinic, cutaneous vasodilatation in women. This will stimulate future studies assessing the pathophysiological significance of the augmented microvascular responsiveness in older women compared to their young counterparts. ABSTRACT We previously reported that ageing attenuates adenosine triphosphate (ATP)-induced, but not muscarinic and nicotinic, cutaneous vasodilatation in men, and that ageing may augment cutaneous vascular responses in women. In the present study, we evaluated the hypothesis that ageing augments muscarinic, nicotinic and/or ATP-mediated cutaneous vasodilatation in healthy women. In 11 young (23 ± 5 years) and 11 older (60 ± 8 years) women, cutaneous vascular conductance was evaluated at three forearm skin sites that were perfused with (1) methacholine (muscarinic receptor agonist, 5 doses: 0.0125, 0.25, 5, 100, 2000 mm), (2) nicotine (nicotinic receptor agonist, 5 doses: 1.2, 3.6, 11, 33, 100 mm), or (3) ATP (purinergic receptor agonist, 5 doses: 0.03, 0.3, 3, 30, 300 mm). Each agonist was administered for 25 min per dose. Methacholine-induced increases in cutaneous vascular conductance were not different between groups at all doses (all P > 0.05). However, a nicotine-induced elevation in cutaneous vascular conductance at the lowest concentration (1.2 mm) was greater in older vs. young women (43 ± 15 vs. 26 ± 10%max, P = 0.04). ATP-induced increases in cutaneous vascular conductance at moderate and high doses (3 and 30 mm) were also greater in older relative to young women (3 mm, 44 ± 11 vs. 28 ± 10%max, P = 0.02; 30 mm, 83 ± 14 vs. 64 ± 17%max, P = 0.05). Therefore, ageing augments nicotinic and ATP-induced, but not muscarinic, cutaneous vasodilatation in women.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada.,Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Gregory W McGarr
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
| | - Ronald J Sigal
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada.,Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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9
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Mack GW, Smith BS, Rowland B. TEA-sensitive K + channels and human eccrine sweat gland output. J Appl Physiol (1985) 2019; 127:921-929. [PMID: 31465715 DOI: 10.1152/japplphysiol.00308.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cholinergic-activated sweating depends on an influx of Ca2+ from extracellular fluid. It is thought that the opening of K+ channels on secretory epithelial cells facilitates Ca2+ 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 log10 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 EC50 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 (KCa1.1 and Kv channels) contribute to eccrine sweat production.
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Affiliation(s)
- Gary W Mack
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Benjamin S Smith
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Benjamin Rowland
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
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10
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Fujii N, McGarr GW, Ichinose M, Nishiyasu T, Kenny GP. Tetraethylammonium, glibenclamide, and 4‐aminopyridine modulate post‐occlusive reactive hyperemia in non‐glabrous human skin with no roles of
NOS
and
COX. Microcirculation 2019; 27:e12586. [DOI: 10.1111/micc.12586] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 07/25/2019] [Accepted: 08/18/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Naoto Fujii
- Faculty of Health and Sport Sciences University of Tsukuba Tsukuba City Japan
| | - Gregory W. McGarr
- Human and Environmental Physiology Research Unit University of Ottawa Ottawa ON Canada
| | - Masashi Ichinose
- Human Integrative Physiology Laboratory School of Business Administration Meiji University Tokyo Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences University of Tsukuba Tsukuba City Japan
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit University of Ottawa Ottawa ON Canada
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11
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Fujii N, Hatam K, McGarr GW, Meade RD, Boulay P, Nishiyasu T, Kenny GP. Exogenous Activation of Protease-Activated Receptor 2 Attenuates Cutaneous Vasodilatation and Sweating in Older Men Exercising in the Heat. Skin Pharmacol Physiol 2019; 32:235-243. [PMID: 31220834 DOI: 10.1159/000500643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 04/26/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Protease-activated receptor 2 (PAR2) exists in the cutaneous vasculature and eccrine sweat glands. We previously showed that in young habitually active men, exogenous PAR2 activation via the agonist SLIGKV-NH2 had no effect on heat loss responses of cutaneous vasodilatation and sweating during rest or exercise in the heat. However, ageing is associated with altered mechanisms governing these responses. Thus, the effect of exogenous PAR2 activation on cutaneous vasodilatation and sweating in older individuals may differ from that in young adults. METHODS Local cutaneous vascular conductance (CVC) and sweat rate were measured in 9 older males (62 ± 4 years) at four forearm skin sites treated with the following: (1) lactated Ringer solution (control), (2) 0.05 mM, (3) 0.5 mM, or (4) 5 mM SLIGKV-NH2. Measurements were performed while participants rested in a non-heat-stress environment (25°C) for ∼60 min and an additional 50 min thereafter in the heat (40°C). Participants then performed 50 min of cycling at a fixed metabolic heat load of 200 W/m2 (to maintain the same thermal drive for heat loss between participants) followed by a 30-min recovery. RESULTS CVC during non-heat-stress resting was elevated from the control site with 5 mM SLIGKV-NH2 (p ≤ 0.05), but this response was not observed during ambient heat exposure. By contrast, 5 mM SLIGKV-NH2 lowered CVC during the early stage (10 and 20 min) of exercise compared to the control site (all p ≤ 0.05). Although sweating during non-heat-stressed and heat-stressed resting was not affected by any dose of SLIGKV-NH2, it was reduced with all SLIGKV-NH2 doses relative to the control site during and following exercise (all p ≤ 0.05). CONCLUSION We show that while exogenous PAR2 activation induces cutaneous vasodilatation at rest under non-heat-stressed conditions, it attenuates cutaneous vasodilatation and sweating during and following an exercise-induced heat stress in older men.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada, .,Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan,
| | - Kion Hatam
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
| | - Gregory W McGarr
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Québec, Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
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Fujii N, McGarr GW, Nishiyasu T, Sigal RJ, Boulay P, Kenny GP. Ageing attenuates muscarinic‐mediated sweating differently in men and women with no effect on nicotinic‐mediated sweating. Exp Dermatol 2019; 28:968-971. [DOI: 10.1111/exd.13878] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 11/03/2018] [Accepted: 01/01/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Naoto Fujii
- Faculty of Health and Sport SciencesUniversity of Tsukuba Tsukuba Japan
- Human and Environmental Physiology Research UnitUniversity of Ottawa Ottawa Ontario Canada
| | - Gregory W. McGarr
- Human and Environmental Physiology Research UnitUniversity of Ottawa Ottawa Ontario Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport SciencesUniversity of Tsukuba Tsukuba Japan
| | - Ronald J. Sigal
- Human and Environmental Physiology Research UnitUniversity of Ottawa Ottawa Ontario Canada
- Departments of MedicineCardiac Sciences and Community Health SciencesFaculties of Medicine and KinesiologyUniversity of Calgary Calgary Alberta Canada
- Clinical Epidemiology ProgramOttawa Hospital Research Institute Ottawa Ontario Canada
| | - Pierre Boulay
- Faculty of Physical Activity SciencesUniversity of Sherbrooke Sherbrooke Quebec Canada
| | - Glen P. Kenny
- Human and Environmental Physiology Research UnitUniversity of Ottawa Ottawa Ontario Canada
- Clinical Epidemiology ProgramOttawa Hospital Research Institute Ottawa Ontario Canada
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Hearon CM, Richards JC, Racine ML, Luckasen GJ, Larson DG, Dinenno FA. Amplification of endothelium-dependent vasodilatation in contracting human skeletal muscle: role of K IR channels. J Physiol 2018; 597:1321-1335. [PMID: 30506579 DOI: 10.1113/jp276998] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/29/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS In humans, the vasodilatory response to skeletal muscle contraction is mediated in part by activation of inwardly rectifying potassium (KIR ) channels. Evidence from animal models suggest that KIR channels serve as electrical amplifiers of endothelium-dependent hyperpolarization (EDH). We found that skeletal muscle contraction amplifies vasodilatation to the endothelium-dependent agonist ACh, whereas there was no change in the vasodilatory response to sodium nitroprusside, an endothelium-independent nitric oxide donor. Blockade of KIR channels reduced the exercise-induced amplification of ACh-mediated vasodilatation. Conversely, pharmacological activation of KIR channels in quiescent muscle via intra-arterial infusion of KCl independently amplified the vasodilatory response to ACh. This study is the first in humans to demonstrate that specific endothelium-dependent vasodilatory signalling is amplified in the vasculature of contracting skeletal muscle and that KIR channels may serve as amplifiers of EDH-like vasodilatory signalling in humans. ABSTRACT The local vasodilatory response to muscle contraction is due in part to the activation of inwardly rectifying potassium (KIR ) channels. Evidence from animal models suggest that KIR channels function as 'amplifiers' of endothelium-dependent vasodilators. We tested the hypothesis that contracting muscle selectively amplifies endothelium-dependent vasodilatation via activation of KIR channels. We measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (FVC) to local intra-arterial infusion of ACh (endothelium-dependent dilator) during resting conditions, handgrip exercise (5% maximum voluntary contraction) or sodium nitroprusside (SNP; endothelium-independent dilator) which served as a high-flow control condition (n = 7, young healthy men and women). Trials were performed before and after blockade of KIR channels via infusion of barium chloride. Exercise augmented peak ACh-mediated vasodilatation (ΔFVC saline: 117 ± 14; exercise: 236 ± 21 ml min-1 (100 mmHg)-1 ; P < 0.05), whereas SNP did not impact ACh-mediated vasodilatation. Blockade of KIR channels attenuated the exercise-induced augmentation of ACh. In eight additional subjects, SNP was administered as the experimental dilator. In contrast to ACh, exercise did not alter SNP-mediated vasodilatation (ΔFVC saline: 158 ± 35; exercise: 121 ± 22 ml min-1 (100 mmHg)-1 ; n.s.). Finally, in a subset of six subjects, direct pharmacological activation of KIR channels in quiescent muscle via infusion of KCl amplified peak ACh-mediated vasodilatation (ΔFVC saline: 97 ± 15, KCl: 142 ± 16 ml min-1 (100 mmHg)-1 ; respectively; P < 0.05). These findings indicate that skeletal muscle contractions selectively amplify endothelium-dependent vasodilatory signalling via activation of KIR channels, and this may be an important mechanism contributing to the normal vasodilatory response to exercise in humans.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Mathew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, 80523, USA
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Fujii N, Danquah MO, Meade RD, Nishiyasu T, Kenny GP. The effect of exogenous activation of protease-activated receptor 2 on cutaneous vasodilatation and sweating in young males during rest and exercise in the heat. Temperature (Austin) 2018; 5:257-266. [PMID: 30377641 PMCID: PMC6205008 DOI: 10.1080/23328940.2018.1506563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Protease-activated receptor 2 (PAR2) exists in the endothelial cells of skin vessels and eccrine sweat glands. We evaluated the hypothesis that exogeneous activation of PAR2 augments cutaneous vasodilatation and sweating during rest and exercise in the heat. In 10 young males (23 ± 5 y), cutaneous vascular conductance (CVC) and sweat rate were measured at four forearm skin sites treated with either 1) lactated Ringer (Control), 2) 0.05 mM, 3) 0.5 mM, or 4) 5 mM SLIGKV-NH2 (PAR2 agonist). Participants initially rested in a semi-recumbent posture under a normothermic ambient condition (25°C) for ~60 min. Thereafter, ambient temperature was increased to 35°C while the participants rested for an additional 60 min. Participants then performed a 50-min bout of cycling (~55% of their pre-determined peak oxygen uptake) followed by a 30-min recovery period. Administration of 5 mM SLIGKV-NH2 increased cutaneous vascular conductance relative to the Control site during normothermic resting (P ≤ 0.05). However, we showed that relative to the Control site, no effect on CVC was observed for any administered dose of SLIGKV-NH2 (0.05-5 mM) during rest (33-39%max CVC), end-exercise (68-70%max CVC), and postexercise recovery (49-53%max CVC) in the heat (all P > 0.05). There were no differences in sweat rate between the Control and all SLIGKV-NH2-treated sites throughout the protocol (0.21-0.23, 1.20-1.27, and 0.32-0.33 mg∙min-1∙cm-2 for rest, end-exercise, and postexercise in the heat, respectively, all P > 0.05). We show that while exogeneous PAR2 activation induces cutaneous vasodilatation during normothermic rest, it does not influence the cutaneous blood flow and sweating responses during rest, exercise or recovery in the heat.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Mercy O. Danquah
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Robert D. Meade
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
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Fujii N, Pastore OL, McGarr GW, Meade RD, McNeely BD, Nishiyasu T, Kenny GP. Cyclooxygenase-1 and -2 modulate sweating but not cutaneous vasodilation during exercise in the heat in young men. Physiol Rep 2018; 6:e13844. [PMID: 30175553 PMCID: PMC6119687 DOI: 10.14814/phy2.13844] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 08/02/2018] [Indexed: 12/16/2022] Open
Abstract
We recently reported that the nonselective cyclooxygenase (COX) inhibitor ketorolac attenuated sweating but not cutaneous vasodilation during moderate-intensity exercise in the heat. However, the specific contributions of COX-1 and COX-2 to the sweating response remained to be determined. We tested the hypothesis that COX-1 but not COX-2 contributes to sweating with no role for either COX isoform in cutaneous vasodilation during moderate-intensity exercise in the heat. In thirteen young males (22 ± 2 years), sweat rate and cutaneous vascular conductance were measured at three forearm skin sites that were continuously treated with (1) lactated Ringer's solution (Control), (2) 150 μmmol·L-1 celecoxib, a selective COX-2 inhibitor, or (3) 10 mmol L-1 ketorolac, a nonselective COX inhibitor. Participants first rested in a non heat stress condition (≥85 min, 25°C) followed by a further 70-min rest period in the heat (35°C). They then performed 50 min of moderate-intensity cycling (~55% peak oxygen uptake) followed by a 30-min recovery period. At the end of exercise, sweat rate was lower at the 150 μmol·L-1 celecoxib (1.51 ± 0.25 mg·min-1 ·cm-2 ) and 10 mmol·L-1 ketorolac (1.30 ± 0.30 mg·min-1 ·cm-2 ) treated skin sites relative to the Control site (1.89 ± 0.27 mg·min-1 ·cm-2 ) (both P ≤ 0.05). Additionally, sweat rate at the ketorolac site was attenuated relative to the celecoxib site (P ≤ 0.05). Neither celecoxib nor ketorolac influenced cutaneous vascular conductance throughout the experiment (both P > 0.05). We showed that both COX-1 and COX-2 contribute to sweating but not cutaneous vasodilation during moderate-intensity exercise in the heat in young men.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research UnitUniversity of OttawaOttawaCanada
- Faculty of Health and Sport SciencesUniversity of TsukubaTsukubaJapan
| | - Olivia L. Pastore
- Human and Environmental Physiology Research UnitUniversity of OttawaOttawaCanada
| | - Gregory W. McGarr
- Human and Environmental Physiology Research UnitUniversity of OttawaOttawaCanada
| | - Robert D. Meade
- Human and Environmental Physiology Research UnitUniversity of OttawaOttawaCanada
| | - Brendan D. McNeely
- Human and Environmental Physiology Research UnitUniversity of OttawaOttawaCanada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport SciencesUniversity of TsukubaTsukubaJapan
| | - Glen P. Kenny
- Human and Environmental Physiology Research UnitUniversity of OttawaOttawaCanada
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16
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Fujii N, Nishiyasu T, Sigal RJ, Boulay P, McGarr GW, Kenny GP. Aging attenuates adenosine triphosphate-induced, but not muscarinic and nicotinic, cutaneous vasodilation in men. Microcirculation 2018; 25:e12462. [PMID: 29846993 DOI: 10.1111/micc.12462] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 05/13/2018] [Accepted: 05/28/2018] [Indexed: 12/22/2022]
Abstract
OBJECTIVE We evaluated the hypothesis that aging attenuates muscarinic, nicotinic, and ATP-related cutaneous vasodilation. METHODS In 11 young (24 ± 4 years) and 11 older males (61 ± 8 years), CVC was assessed at 3 forearm skin sites that were infused with either: (i) methacholine (muscarinic receptor agonist, 5 doses: 0.0125, 0.25, 5, 100, 2000 mmol/L), (ii) nicotine (nicotinic receptor agonist, 5 doses: 1.2, 3.6, 11, 33, 100 mmol/L), or (iii) ATP (purinergic receptor agonist, 5 doses: 0.03, 0.3, 3, 30, 300 mmol/L). Each agonist was administered for 25 minutes per dose. RESULTS We showed that CVC at all doses of methacholine did not differ between groups. Similarly, no between-group differences in CVC were observed during nicotine administration at all doses administered. By contrast, while no differences in CVC were measured during the administration of ATP at low (0.03 and 0.3 mmol/L) or high (300 mmol/L) concentrations, CVC was reduced in the older relative to the young males at moderate concentrations of ATP (3 mmol/L: 23 ± 6 vs 40 ± 13%max, 30 mmol/L: 62 ± 11 vs 83 ± 8%max, both P ≤ .05). CONCLUSIONS We show that aging attenuates ATP-induced, but not muscarinic or nicotinic, cutaneous vasodilation in men.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada.,Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Ronald J Sigal
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada.,Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Gregory W McGarr
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
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Postsynaptic cutaneous vasodilation and sweating: influence of adiposity and hydration status. Eur J Appl Physiol 2018; 118:1703-1713. [PMID: 29855792 DOI: 10.1007/s00421-018-3902-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/24/2018] [Indexed: 10/14/2022]
Abstract
INTRODUCTION Obesity and hypohydration independently affect postsynaptic endothelial function, but it is unknown if hypohydration affects lean and obese individuals differently. PURPOSE To examine the effect of hypohydration on postsynaptic cutaneous vasodilation and sweating in men with high and low adiposity (HI- and LO-BF, respectively). METHODS Ten males with LO-BF and ten with HI-BF were instrumented for forearm microdialysis when euhydrated and hypohydrated. Changes in cutaneous vascular conductance (CVC) with intradermal infusion of sodium nitroprusside (SNP) and methacholine chloride (MCh) were assessed. Local sweat rate (LSR) was simultaneously assessed at the MCh site. At the end of the last dose, maximal CVC was elicited by delivering a maximal dose of SNP for 30 min to both sites with simultaneous local heating at the SNP site. The concentration of drug needed to elicit 50% of the maximal response (EC50) was compared between groups and hydration conditions. RESULTS When euhydrated, EC50 of MCh-induced CVC was not different between LO- vs. HI-BF [- 3.04 ± 0.12 vs. - 2.98 ± 0.19 log (MCh) M, P = 0.841]. EC50 of SNP-induced CVC was higher in euhydrated HI- vs. LO-BF (- 1.74 ± 0.17 vs. - 2.13 ± 0.06 log (SNP) M, P = 0.034). Within each group, hydration status did not change MCh- or SNP-induced CVC (P > 0.05). LSR was not different between groups or hydration condition (P > 0.05). CONCLUSIONS These data suggest reduced sensitivity of endothelium-independent vasodilation in individuals with high adiposity when euhydrated. However, hypohydration does not affect cutaneous vasodilation or local sweat rate differently between individuals with low or high adiposity.
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18
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Fujii N, Meade RD, McNeely BD, Nishiyasu T, Sigal RJ, Kenny GP. Type 2 diabetes specifically attenuates purinergic skin vasodilatation without affecting muscarinic and nicotinic skin vasodilatation and sweating. Exp Physiol 2018; 103:212-221. [DOI: 10.1113/ep086694] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/28/2017] [Indexed: 01/12/2023]
Affiliation(s)
- Naoto Fujii
- Faculty of Health and Sport Sciences; University of Tsukuba; Tsukuba Japan
- Human and Environmental Physiology Research Unit; University of Ottawa; Ottawa Ontario Canada
| | - Robert D. Meade
- Human and Environmental Physiology Research Unit; University of Ottawa; Ottawa Ontario Canada
| | - Brendan D. McNeely
- Human and Environmental Physiology Research Unit; University of Ottawa; Ottawa Ontario Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences; University of Tsukuba; Tsukuba Japan
| | - Ronald J. Sigal
- Human and Environmental Physiology Research Unit; University of Ottawa; Ottawa Ontario Canada
- Department of Medicine; Cumming School of Medicine, University of Calgary; Calgary Alberta Canada
- Clinical Epidemiology Program; Ottawa Hospital Research Institute; Ottawa Ontario Canada
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit; University of Ottawa; Ottawa Ontario Canada
- Clinical Epidemiology Program; Ottawa Hospital Research Institute; Ottawa Ontario Canada
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19
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Fujii N, McNeely BD, Nishiyasu T, Kenny GP. Intradermal administration of atrial natriuretic peptide has no effect on sweating and cutaneous vasodilator responses in young male adults. Temperature (Austin) 2017; 4:406-413. [PMID: 29435479 DOI: 10.1080/23328940.2017.1356433] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 07/07/2017] [Accepted: 07/07/2017] [Indexed: 01/27/2023] Open
Abstract
Atrial natriuretic peptide (ANP) increases during exercise in the heat wherein heat loss responses of sweating and cutaneous vasodilatation are activated. Hence ANP might be involved in the regulation of sweating and cutaneous vasodilatation. However, whether ANP directly mediates sweating and cutaneous vasodilatation needs to be clarified. Also, muscarinic receptor activation induces sweating and cutaneous vasodilatation, however, it remains to be determined whether ANP modulates these responses. In this study, in 11 young males (25 ± 5 years), cutaneous vascular conductance and sweat rate were assessed at intradermal microdialysis sites that were continuously perfused with either lactated Ringer (Control) or 3 different concentrations of ANP (0.1, 1, 10 µM). All 4 sites were co-administrated with methacholine, a muscarinic receptor agonist, in a dose-dependent fashion (0.0125, 0.25, 5, 100, and 2000 mM, 25 min for each). ANP at all concentrations did not increase sweat rate and cutaneous vascular conductance as compared with pre-ANP infusion values (all P > 0.05). Methacholine increased both sweat rate and cutaneous vascular conductance (all P ≤ 0.05). However, the responses were unaffected by co-administration of ANP relative to methacholine only, even as assessed in context of the methacholine concentration required to elicit 50% of the maximal response (EC50) (all P > 0.05). We show that exogenous ANP administration intradermally does not directly modulate sweating and cutaneous vasodilatation under room temperature conditions in resting young adults. Further, there is no effect of ANP on muscarinic sweating and cutaneous vasodilatation.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada.,Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan
| | - Brendan D McNeely
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Takeshi Nishiyasu
- Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
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Fujii N, Zhang SY, McNeely BD, Nishiyasu T, Kenny GP. Heat shock protein 90 contributes to cutaneous vasodilation through activating nitric oxide synthase in young male adults exercising in the heat. J Appl Physiol (1985) 2017; 123:844-850. [PMID: 28751373 PMCID: PMC5668448 DOI: 10.1152/japplphysiol.00446.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 07/25/2017] [Accepted: 07/25/2017] [Indexed: 12/25/2022] Open
Abstract
While the mechanisms underlying the control of cutaneous vasodilation have been extensively studied, there remains a lack of understanding of the different factors that may modulate cutaneous perfusion during an exercise-induced heat stress. We evaluated the hypothesis that heat shock protein 90 (HSP90) contributes to the heat loss response of cutaneous vasodilation via the activation of nitric oxide synthase (NOS) during exercise in the heat. In 11 young males (25 ± 5 yr), cutaneous vascular conductance (CVC) was measured at four forearm skin sites that were continuously treated with 1) lactated Ringer solution (control), 2) NOS inhibition with 10 mM NG-nitro-l-arginine methyl ester (l-NAME), 3) HSP90 inhibition with 178 μM geldanamycin, or 4) a combination of 10 mM l-NAME and 178 μM geldanamycin. Participants rested in a moderate heat stress (35°C) condition for 70 min. Thereafter, they performed a 50-min bout of moderate-intensity cycling (~52% V̇o2peak) followed by a 30-min recovery period. We showed that NOS inhibition attenuated CVC (~40-50%) relative to the control site during pre- and postexercise rest in the heat (P ≤ 0.05); however, no effect of HSP90 inhibition was observed (P > 0.05). During exercise, we observed an attenuation of CVC with the separate inhibition of NOS (~40-50%) and HSP90 (~15-20%) compared with control (both P ≤ 0.05). However, the effect of HSP90 inhibition was absent in the presence of the coinhibition of NOS (P > 0.05). We show that HSP90 contributes to cutaneous vasodilation in young men exposed to the heat albeit during exercise only. We also show that the HSP90 contribution is due to NOS-dependent mechanisms.NEW & NOTEWORTHY We show that heat shock protein 90 functionally contributes to the heat loss response of cutaneous vasodilation during exercise in the heat, and this response is mediated through the activation of nitric oxide synthase. Therefore, interventions that may activate heat shock protein 90 may facilitate an increase in heat dissipation through an augmentation of cutaneous perfusion. In turn, this may attenuate or reduce the increase in core temperature and therefore the level of heat strain.
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Affiliation(s)
- Naoto Fujii
- Faculty of Health and Sports Science, University of Tsukuba, Tsukuba, Japan; and
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Sarah Y Zhang
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Brendan D McNeely
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sports Science, University of Tsukuba, Tsukuba, Japan; and
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
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21
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Burnstock G. Purinergic Signaling in the Cardiovascular System. Circ Res 2017; 120:207-228. [PMID: 28057794 DOI: 10.1161/circresaha.116.309726] [Citation(s) in RCA: 267] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/21/2016] [Accepted: 11/23/2016] [Indexed: 02/07/2023]
Abstract
There is nervous control of the heart by ATP as a cotransmitter in sympathetic, parasympathetic, and sensory-motor nerves, as well as in intracardiac neurons. Centers in the brain control heart activities and vagal cardiovascular reflexes involve purines. Adenine nucleotides and nucleosides act on purinoceptors on cardiomyocytes, AV and SA nodes, cardiac fibroblasts, and coronary blood vessels. Vascular tone is controlled by a dual mechanism. ATP, released from perivascular sympathetic nerves, causes vasoconstriction largely via P2X1 receptors. Endothelial cells release ATP in response to changes in blood flow (via shear stress) or hypoxia, to act on P2 receptors on endothelial cells to produce nitric oxide, endothelium-derived hyperpolarizing factor, or prostaglandins to cause vasodilation. ATP is also released from sensory-motor nerves during antidromic reflex activity, to produce relaxation of some blood vessels. Purinergic signaling is involved in the physiology of erythrocytes, platelets, and leukocytes. ATP is released from erythrocytes and platelets, and purinoceptors and ectonucleotidases are expressed by these cells. P1, P2Y1, P2Y12, and P2X1 receptors are expressed on platelets, which mediate platelet aggregation and shape change. Long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides promote migration and proliferation of vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis, vessel remodeling during restenosis after angioplasty and atherosclerosis. The involvement of purinergic signaling in cardiovascular pathophysiology and its therapeutic potential are discussed, including heart failure, infarction, arrhythmias, syncope, cardiomyopathy, angina, heart transplantation and coronary bypass grafts, coronary artery disease, diabetic cardiomyopathy, hypertension, ischemia, thrombosis, diabetes mellitus, and migraine.
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Affiliation(s)
- Geoffrey Burnstock
- From the Autonomic Neuroscience Institute, Royal Free and University College Medical School, London, United Kingdom.
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Lang JA, Krajek AC, Smaller KA. Evidence for a functional vasoconstrictor role for ATP in the human cutaneous microvasculature. Exp Physiol 2017; 102:684-693. [PMID: 28295755 DOI: 10.1113/ep086231] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/06/2017] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the central question of this study? In young adults, about half of the cold-related reduction in skin blood flow during cold exposure is mediated by noradrenaline, while the remainder is attributable to other substances co-released with noradrenaline that have yet to be identified. What is the main finding and its importance? Purinergic receptor blockade blunted the vasoconstriction response to whole-body cooling and to intradermal administration of tyramine. These results indicate that ATP is necessary to vasoconstrict blood vessels in the skin adequately and prevent heat loss in a cold environment. Noradrenaline is responsible for eliciting ∼60% of the reflex cutaneous vasoconstriction (VC) response in young adults, while the remainder is attributable to one or more unidentified co-released sympathetic adrenergic neurotransmitter(s). Inconsistent evidence has placed neuropeptide Y in this role; however, other putative cotransmitters have yet to be tested. We hypothesize that ATP contributes to the reflex cutaneous VC response. Two protocols were conducted in young adults (n = 10); both involved the placement of three microdialysis probes in forearm skin and whole-body cooling (skin temperature = 30.5°C). In protocol 1, the following solutions were infused: (i) lactated Ringer solution (control); (ii) 10 mm l-NAME; and (iii) purinergic receptor blockade with 1 mm suramin plus l-NAME. In protocol 2, the following solutions were infused: (i) lactated Ringer solution; (ii) suramin plus l-NAME; and (iii) suramin plus l-NAME plus adrenoreceptor blockade with 5 mm yohimbine plus 1 mm propranolol. Laser Doppler flux (LDF) was measured over each microdialysis site, and cutaneous vascular conductance (CVC) was calculated (CVC = LDF/MAP) and expressed as percentage changes from baseline (%ΔCVCBASELINE ). l-NAME was used to block the vasodilatory influence of ATP and unmask the P2 X-mediated VC response to exogenous ATP infusion (-21 ± 6%ΔCVCBASELINE ). During cooling, the VC response (control, -39 ± 8%ΔCVCBASELINE ) was attenuated at the suramin site (-21 ± 4%ΔCVCBASELINE ) and further blunted with combined adrenoreceptor blockade (-9 ± 3%ΔCVCBASELINE ; P < 0.05). Compared with the control site (-22 ± 5%ΔCVCBASELINE ), suramin inhibited pharmacologically induced VC to tyramine (-12 ± 6%ΔCVCBASELINE ; P < 0.05), which displaces adrenergic neurotransmitters from axon terminals. These data indicate that ATP contributes to the cutaneous VC response in humans.
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Affiliation(s)
- James A Lang
- Department of Physical Therapy, Des Moines University, Des Moines, IA, USA
| | - Alex C Krajek
- Department of Physical Therapy, Des Moines University, Des Moines, IA, USA
| | - Kevin A Smaller
- Department of Neuroscience, Drake University, Des Moines, IA, USA
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Fujii N, McNeely BD, Nishiyasu T, Kenny GP. Prostacyclin does not affect sweating but induces skin vasodilatation to a greater extent in older versus younger women: roles of NO and K Ca channels. Exp Physiol 2017; 102:578-586. [PMID: 28271565 DOI: 10.1113/ep086297] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/02/2017] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? It remains unknown whether ageing modulates prostacyclin-induced cutaneous vasodilatation in women. What is the main finding and its importance? Prostacyclin induced cutaneous vasodilatation, albeit the magnitude of increase at lower concentrations of prostacyclin was greater in older relative to young women. This response was associated with greater contributions of nitric oxide synthase and calcium-activated potassium channels. Our results suggest that administration of prostacyclin might be an effective therapy to reverse microvascular hypoperfusion, especially in older women. We previously reported that prostacyclin induces cutaneous vasodilatation but not sweating in younger and older men. Furthermore, we demonstrated that nitric oxide synthase and calcium-activated potassium (KCa ) channels contribute to the prostacyclin-induced cutaneous vasodilatation in younger men, although these contributions are diminished in older men. Given that the effects of ageing might differ between men and women, the above results cannot simply be applied to women. In this study, cutaneous vascular conductance and sweat rate were evaluated in younger (mean ± SD, 22 ± 3 years old) and older (55 ± 7 years old) women (10 per group) at four intradermal forearm skin sites treated as follows: (i) lactated Ringer solution without any drug (control); (ii) 10 mm NG -nitro-l-arginine (l-NNA), a non-specific nitric oxide synthase inhibitor; (iii) 50 mm tetraethylammonium (TEA), a non-specific KCa channel blocker; or (iv) 10 mm l-NNA plus 50 mm TEA. All four sites were co-administered with prostacyclin in an incremental manner (0.04, 0.4, 4, 40 and 400 μm, each for 25 min). Surprisingly, increases in cutaneous vascular conductance in response to 0.04-4 μm prostacyclin were greater in older relative to younger women (all P ≤ 0.05), and these age-related differences were diminished when both l-NNA and TEA were administered simultaneously (all P > 0.05). No effect on sweat rate was observed in either group (all concentrations, P > 0.05). We show that although prostacyclin does not mediate sweating, it induces cutaneous vasodilatation, and this response elicited by lower concentrations of prostacyclin is greater in older relative to younger women. This greater cutaneous vasodilatation in older women is likely to be attributable to nitric oxide synthase- and KCa channel-dependent mechanisms.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada.,Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan
| | - Brendan D McNeely
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
| | - Takeshi Nishiyasu
- Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
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Fujii N, Louie JC, McNeely BD, Zhang SY, Tran MA, Kenny GP. Nicotinic receptor activation augments muscarinic receptor-mediated eccrine sweating but not cutaneous vasodilatation in young males. Exp Physiol 2016; 102:245-254. [DOI: 10.1113/ep085916] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 11/15/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics; University of Ottawa; Ottawa Ontario Canada
| | - Jeffrey C. Louie
- Human and Environmental Physiology Research Unit, School of Human Kinetics; University of Ottawa; Ottawa Ontario Canada
| | - Brendan D. McNeely
- Human and Environmental Physiology Research Unit, School of Human Kinetics; University of Ottawa; Ottawa Ontario Canada
| | - Sarah Y. Zhang
- Human and Environmental Physiology Research Unit, School of Human Kinetics; University of Ottawa; Ottawa Ontario Canada
| | - My-An Tran
- Human and Environmental Physiology Research Unit, School of Human Kinetics; University of Ottawa; Ottawa Ontario Canada
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics; University of Ottawa; Ottawa Ontario Canada
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Fujii N, Amano T, Halili L, Louie JC, Zhang SY, McNeely BD, Kenny GP. Intradermal administration of endothelin-1 attenuates endothelium-dependent and -independent cutaneous vasodilation via Rho kinase in young adults. Am J Physiol Regul Integr Comp Physiol 2016; 312:R23-R30. [PMID: 27881399 DOI: 10.1152/ajpregu.00368.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/31/2016] [Accepted: 11/18/2016] [Indexed: 01/02/2023]
Abstract
We recently showed that intradermal administration of endothelin-1 diminished endothelium-dependent and -independent cutaneous vasodilation. We evaluated the hypothesis that Rho kinase may be a mediator of this response. We also sought to evaluate if endothelin-1 increases sweating. In 12 adults (25 ± 6 yr), we measured cutaneous vascular conductance (CVC) and sweating during 1) endothelium-dependent vasodilation induced via administration of incremental doses of methacholine (0.25, 5, 100, and 2,000 mM each for 25 min) and 2) endothelium-independent vasodilation induced via administration of 50 mM sodium nitroprusside (20-25 min). Responses were evaluated at four skin sites treated with either 1) lactated Ringer solution (Control), 2) 400 nM endothelin-1, 3) 3 mM HA-1077 (Rho kinase inhibitor), or 4) endothelin-1+HA-1077. Pharmacological agents were intradermally administered via microdialysis. Relative to the Control site, endothelin-1 attenuated endothelium-dependent vasodilation (CVC at 2,000 mM methacholine, 80 ± 10 vs. 56 ± 15%max, P < 0.01); however, this response was not detected when the Rho kinase inhibitor was simultaneously administered (CVC at 2,000 mM methacholine for Rho kinase inhibitor vs. endothelin-1 + Rho kinase inhibitor sites: 73 ± 9 vs. 72 ± 11%max, P > 0.05). Endothelium-independent vasodilation was attenuated by endothelin-1 compared with the Control site (CVC, 92 ± 13 vs. 70 ± 14%max, P < 0.01). However, in the presence of Rho kinase inhibition, endothelin-1 did not affect endothelium-independent vasodilation (CVC at Rho kinase inhibitor vs. endothelin-1+Rho kinase inhibitor sites: 81 ± 9 vs. 86 ± 10%max, P > 0.05). There was no between-site difference in sweating throughout (P > 0.05). We show that in young adults, Rho kinase is an important mediator of the endothelin-1-mediated attenuation of endothelium-dependent and -independent cutaneous vasodilation, and that endothelin-1 does not increase sweating.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Tatsuro Amano
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Lyra Halili
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Jeffrey C Louie
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Sarah Y Zhang
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Brendan D McNeely
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
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Metzler-Wilson K, Wilson TE. Impact of calcium regulation on eccrine sweating and sweating disorders: the view from cells to glands to intact human skin. Exp Physiol 2016; 101:345-6. [PMID: 27203840 DOI: 10.1113/ep085639] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | - Thad E Wilson
- Marian University College of Osteopathic Medicine, Indianapolis, IN, USA
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Halili L, Singh MS, Fujii N, Alexander LM, Kenny GP. Endothelin-1 modulates methacholine-induced cutaneous vasodilatation but not sweating in young human skin. J Physiol 2016; 594:3439-52. [PMID: 26846374 DOI: 10.1113/jp271735] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/29/2016] [Indexed: 12/15/2022] Open
Abstract
KEY POINTS Endothelin-1 (ET-1) is a potent endothelial-derived vasoconstrictor that may modulate cholinergic cutaneous vascular regulation. Endothelin receptors are also expressed on the human eccrine sweat gland, although it remains unclear whether ET-1 modulates cholinergic sweating. We investigated whether ET-1 attenuates cholinergic cutaneous vasodilatation and sweating through a nitric oxide synthase (NOS)-dependent mechanism. Our findings show that ET-1 attenuates methacholine-induced cutaneous vasodilatation through a NOS-independent mechanism. We also demonstrate that ET-1 attenuates cutaneous vasodilatation in response to sodium nitroprusside, suggesting that ET-1 diminishes the dilatation capacity of vascular smooth muscle cells. We show that ET-1 does not modulate methacholine-induced sweating at any of the administered concentrations. Our findings advance our knowledge pertaining to the peripheral control underpinning the regulation of cutaneous blood flow and sweating and infer that ET-1 may attenuate the heat loss responses of cutaneous blood flow, but not sweating. ABSTRACT The present study investigated the effect of endothelin-1 (ET-1) on cholinergic mechanisms of end-organs (i.e. skin blood vessels and sweat glands) for heat dissipation. We evaluated the hypothesis that ET-1 attenuates cholinergic cutaneous vasodilatation and sweating through a nitric oxide synthase (NOS)-dependent mechanism. Cutaneous vascular conductance (CVC) and sweat rate were assessed in three protocols: in Protocol 1 (n = 8), microdialysis sites were perfused with lactated Ringer solution (Control), 40 pm, 4 nm or 400 nm ET-1; in Protocol 2 (n = 11) sites were perfused with lactated Ringer solution (Control), 400 nm ET-1, 10 mm N(G) -nitro-l-arginine (l-NNA; a NOS inhibitor) or a combination of 400 nm ET-1 and 10 mm l-NNA; in Protocol 3 (n = 8), only two sites (Control and 400 nm ET-1) were utilized to assess the influence of ET-1 on the dilatation capacity of vascular smooth muscle cells (sodium nitroprusside; SNP). Methacholine (MCh) was co-administered in a dose-dependent manner (0.0125, 0.25, 5, 100, 2000 mm, each for 25 min) at all skin sites. ET-1 at 400 nm (P < 0.05) compared to lower doses (40 pm and 4 nm) (all P > 0.05) significantly attenuated increases in CVC in response to 0.25 and 5 mm MCh. A high dose of ET-1 (400 nm) co-infused with l-NNA further attenuated CVC during 0.25, 5 and 100 mm MCh administration relative to the ET-1 site (all P < 0.05). Cutaneous vasodilatation in response to SNP was significantly blunted after administration of 400 nm ET-1 (P < 0.05). We show that ET-1 attenuates cutaneous vasodilatation through a NOS-independent mechanism, possibly through a vascular smooth muscle cell-dependent mechanism, and methacholine-induced sweating is not altered by ET-1.
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Affiliation(s)
- Lyra Halili
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Maya Sarah Singh
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Lacy M Alexander
- Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park, PA, USA
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
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Meade RD, Louie JC, Poirier MP, McGinn R, Fujii N, Kenny GP. Exploring the mechanisms underpinning sweating: the development of a specialized ventilated capsule for use with intradermal microdialysis. Physiol Rep 2016; 4:e12738. [PMID: 27033452 PMCID: PMC4814883 DOI: 10.14814/phy2.12738] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 02/18/2016] [Indexed: 01/26/2023] Open
Abstract
Many studies have aimed to identify the controllers of sweating using ventilated capsules with intradermal microdialysis. It is unclear, however, if the surface area covered by the capsule influences the observed response as a result of differences in the number of sweat glands affected by the infused pharmacological agent relative to the total glands captured by the capsule. We evaluated the area of skin perfused with agents delivered via microdialysis. Thereafter, we developed a specialized sweat capsule (1.1 cm(2)) and compared the sweating response with a classic capsule (2.8 cm(2)). InProtocol 1(n = 6), methacholine was delivered to forearm skin in a dose-dependent manner (1-2000 mmol L(-1)). The area of activated sweat glands was assessed via the modified iodine-paper technique. InProtocol 2(n = 6), the area of inhibited sweat glands induced by ouabain and atropine was assessed during moderate-intensity cycling. Marked variability in the affected skin area was observed (0.9 ± 0.4 to 5.2 ± 1.1 cm(2)). InProtocol 3(n = 6), we compared the attenuation in local sweat rate (LSR) induced by atropine between the new and classic capsule during moderate-intensity cycling. Atropine attenuated sweating as assessed using the new (control: 0.87 ± 0.23 mg min(-1) cm(-2)vs. atropine: 0.54 ± 0.22 mg min(-1) cm(-2);P < 0.01) and classic (control: 0.85 ± 0.33 mg min(-1) cm(-2)vs. atropine: 0.60 ± 0.26 mg min(-1) cm(-2);P = 0.05) capsule designs. Importantly, responses did not differ between capsule designs (P = 0.23). These findings provide critical information regarding the skin surface area perfused by microdialysis and suggest that use of a larger capsule does not alter the mechanistic insight into the sweating response gained when using microdialysis.
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Affiliation(s)
- Robert D Meade
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Jeffrey C Louie
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Martin P Poirier
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Ryan McGinn
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Naoto Fujii
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
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