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Wong BJ, Turner CG, Hayat MJ, Otis JS, Quyyumi AA. Inhibition of superoxide and iNOS augment cutaneous nitric oxide-dependent vasodilation in non-Hispanic black young adults. Physiol Rep 2024; 12:e16021. [PMID: 38639714 PMCID: PMC11027894 DOI: 10.14814/phy2.16021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 04/04/2024] [Indexed: 04/20/2024] Open
Abstract
We assessed the combined effect of superoxide and iNOS inhibition on microvascular function in non-Hispanic Black and non-Hispanic White participants (n = 15 per group). Participants were instrumented with four microdialysis fibers: (1) lactated Ringer's (control), (2) 10 μM tempol (superoxide inhibition), (3) 0.1 mM 1400 W (iNOS inhibition), (4) tempol + 1400 W. Cutaneous vasodilation was induced via local heating and NO-dependent vasodilation was quantified. At control sites, NO-dependent vasodilation was lower in non-Hispanic Black (45 ± 9% NO) relative to non-Hispanic White (79 ± 9% NO; p < 0.01; effect size, d = 3.78) participants. Tempol (62 ± 16% NO), 1400 W (78 ± 12% NO) and tempol +1400 W (80 ± 13% NO) increased NO-dependent vasodilation in non-Hispanic Black participants relative to control sites (all p < 0.01; d = 1.22, 3.05, 3.03, respectively). The effect of 1400 W (p = 0.04, d = 1.11) and tempol +1400 W (p = 0.03, d = 1.22) was greater than tempol in non-Hispanic Black participants. There was no difference between non-Hispanic Black and non-Hispanic White participants at 1400 W or tempol + 1400 W sites. These data suggest iNOS has a greater effect on NO-dependent vasodilation than superoxide in non-Hispanic Black participants.
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Affiliation(s)
- Brett J. Wong
- Department of Kinesiology & HealthGeorgia State UniversityAtlantaGeorgiaUSA
| | - Casey G. Turner
- Department of Kinesiology & HealthGeorgia State UniversityAtlantaGeorgiaUSA
- Molecular Cardiology Research InstituteTufts Medical CenterBostonMassachusettsUSA
| | - Matthew J. Hayat
- Department of Population Health Sciences, School of Public HealthGeorgia State UniversityAtlantaGeorgiaUSA
| | - Jeffrey S. Otis
- Department of Kinesiology & HealthGeorgia State UniversityAtlantaGeorgiaUSA
| | - Arshed A. Quyyumi
- Emory Clinical Cardiology Research InstituteEmory University School of MedicineAtlantaGeorgiaUSA
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Leon MM, Maștaleru A, Oancea A, Alexa-Stratulat T, Peptu CA, Tamba BI, Harabagiu V, Grosu C, Alexa AI, Cojocaru E. Lidocaine-Liposomes-A Promising Frontier for Transdermal Pain Management. J Clin Med 2024; 13:271. [PMID: 38202278 PMCID: PMC10779996 DOI: 10.3390/jcm13010271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/16/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
(1) Background: We aim to develop novel gel formulations for transdermal drug delivery systems in acute and inflammatory pain therapy. (2) Methods: We induced inflammation by the injection of λ-carrageenan on the hind paw of 80 Wistar male rats. The animals were randomized into eight groups of 10 rats each: C (placebo gel), E (EMLATM), L (lidocaine 2%), L-CD (lidocaine + cyclodextrin 2.5%), L-LP (lidocaine + liposomes 1.7%), L-CS (lidocaine + chitosan 4%), L-CSh (lidocaine + chitosan hydrochloride), and L-CS-LP (lidocaine + chitosan + liposomes). The behavior response was determined with a hot plate, cold plate, and algesimeter, each being performed at 30, 60, 120, 180, and 240 min after pain induction. At the end of the experiment, tissue samples were collected for histological assessment. (3) Results: L-LP had the greatest anesthetic effects, which was proven on the cold plate test compared to placebo and EMLATM (all p ≤ 0.001). L-CS-LP had a significant effect on cold plate evaluation compared to placebo (p ≤ 0.001) and on hot plate evaluation compared to EMLATM (p = 0.018). (4) Conclusions: L-LP is a new substance with a substantial analgesic effect demonstrated by the cold plate in the first 120 min. Further studies with more animals are needed to determine the maximum doses that can be applied for a better analgesia with minimum side effects.
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Affiliation(s)
- Maria Magdalena Leon
- Department of Medical Specialties I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iaşi, Romania;
| | - Alexandra Maștaleru
- Department of Medical Specialties I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iaşi, Romania;
| | - Andra Oancea
- Department of Medical Specialties I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iaşi, Romania;
| | - Teodora Alexa-Stratulat
- Department of Medical Oncology–Radiotherapy, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iaşi, Romania;
| | - Cătălina Anișoara Peptu
- Department of Natural and Synthetic Polymers, Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, 700050 Iasi, Romania;
| | - Bogdan-Ionel Tamba
- CEMEX Laboratory, “Grigore T. Popa” University of Medicine and Pharmacy, 700259 Iaşi, Romania;
| | - Valeria Harabagiu
- “Petru Poni” Institute of Macromolecular Chemistry, 700487 Iaşi, Romania;
| | - Cristina Grosu
- Department of Medical Specialties III, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iaşi, Romania;
| | - Anisia Iuliana Alexa
- Department of Surgery II, Discipline of Ophthalmology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Elena Cojocaru
- Department of Morphofunctional Sciences I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iaşi, Romania;
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Cramer MN, Gagnon D, Laitano O, Crandall CG. Human temperature regulation under heat stress in health, disease, and injury. Physiol Rev 2022; 102:1907-1989. [PMID: 35679471 PMCID: PMC9394784 DOI: 10.1152/physrev.00047.2021] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 05/10/2022] [Accepted: 05/28/2022] [Indexed: 12/30/2022] Open
Abstract
The human body constantly exchanges heat with the environment. Temperature regulation is a homeostatic feedback control system that ensures deep body temperature is maintained within narrow limits despite wide variations in environmental conditions and activity-related elevations in metabolic heat production. Extensive research has been performed to study the physiological regulation of deep body temperature. This review focuses on healthy and disordered human temperature regulation during heat stress. Central to this discussion is the notion that various morphological features, intrinsic factors, diseases, and injuries independently and interactively influence deep body temperature during exercise and/or exposure to hot ambient temperatures. The first sections review fundamental aspects of the human heat stress response, including the biophysical principles governing heat balance and the autonomic control of heat loss thermoeffectors. Next, we discuss the effects of different intrinsic factors (morphology, heat adaptation, biological sex, and age), diseases (neurological, cardiovascular, metabolic, and genetic), and injuries (spinal cord injury, deep burns, and heat stroke), with emphasis on the mechanisms by which these factors enhance or disturb the regulation of deep body temperature during heat stress. We conclude with key unanswered questions in this field of research.
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Affiliation(s)
- Matthew N Cramer
- Defence Research and Development Canada-Toronto Research Centre, Toronto, Ontario, Canada
| | - Daniel Gagnon
- Montreal Heart Institute and School of Kinesiology and Exercise Science, Université de Montréal, Montréal, Quebec, Canada
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
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Razi O, Tartibian B, Teixeira AM, Zamani N, Govindasamy K, Suzuki K, Laher I, Zouhal H. Thermal dysregulation in patients with multiple sclerosis during SARS-CoV-2 infection. The potential therapeutic role of exercise. Mult Scler Relat Disord 2022; 59:103557. [PMID: 35092946 PMCID: PMC8785368 DOI: 10.1016/j.msard.2022.103557] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 01/16/2022] [Accepted: 01/22/2022] [Indexed: 12/15/2022]
Abstract
Thermoregulation is a homeostatic mechanism that is disrupted in some neurological diseases. Patients with multiple sclerosis (MS) are susceptible to increases in body temperature, especially with more severe neurological signs. This condition can become intolerable when these patients suffer febrile infections such as coronavirus disease-2019 (COVID-19). We review the mechanisms of hyperthermia in patients with MS, and they may encounter when infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Finally, the thermoregulatory role and relevant adaptation to regular physical exercise are summarized.
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Affiliation(s)
- Omid Razi
- Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Razi University, Kermanshah, Iran
| | - Bakhtyar Tartibian
- Department of Exercise Physiology, Faculty of Physical Education and Sports Sciences, Allameh Tabataba'i University, Tehran, Iran
| | - Ana Maria Teixeira
- University of Coimbra, Research Center for Sport and Physical Activity, Faculty of Sport Sciences and Physical Education, Coimbra, Portugal
| | - Nastaran Zamani
- Department of Biology, Faculty of Science, Payame-Noor University, Tehran, Iran
| | - Karuppasamy Govindasamy
- Department of Physical Education & Sports Science, SRM Institute of Science and Technology, Kattankulathur, Tamilnadu, India
| | - Katsuhiko Suzuki
- Faculty of Sport Sciences, Waseda University, Tokorozawa 359-1192, Japan.
| | - Ismail Laher
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Hassane Zouhal
- Univ Rennes, M2S (Laboratoire Mouvement, Sport, Santé) - EA 1274, Rennes F-35000, France; Institut International des Sciences du Sport (2I2S), Irodouer 35850, France.
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TRPA1 channel activation with cinnamaldehyde induces cutaneous vasodilation through NOS, but not COX and KCa channel, mechanisms in humans. J Cardiovasc Pharmacol 2021; 79:375-382. [PMID: 34983913 DOI: 10.1097/fjc.0000000000001188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 11/06/2021] [Indexed: 11/25/2022]
Abstract
ABSTRACT Transient receptor potential ankyrin 1 (TRPA1) channel activation induces cutaneous vasodilation in humans in vivo. However, the mechanisms underlying this response remains equivocal. We hypothesized that nitric oxide (NO) synthase (NOS) and Ca2+ activated K+ (KCa) channels contribute to the TRPA1 channel-induced cutaneous vasodilation with no involvement of cyclooxygenase (COX). Cutaneous vascular conductance (CVC) in 9 healthy young adults was assessed at four dorsal forearm skin sites treated by intradermal microdialysis with either: 1) vehicle control (98% propylene glycol + 1.985% dimethyl sulfoxide + 0.015% lactated Ringer solution), 2) 10 mM L-NAME, a non-selective NOS inhibitor, 3) 10 mM ketorolac, a non-selective COX inhibitor, or 4) 50 mM tetraethylammonium, a non-selective KCa channel blocker. Cinnamaldehyde, a TRPA1 channel activator, was administered to each skin site in a dose-dependent manner (2.9, 8.8, 26 and 80 %, each lasting ≥30min). Administration of ≥8.8% cinnamaldehyde increased CVC from baseline at the vehicle control site by as much as 27.4% [95 % confidence interval of 5.3] (P<0.001). NOS inhibitor attenuated the cinnamaldehyde induced-increases in CVC at the 8.8, 26.0, and 80.0% concentrations relative to the vehicle control site (all P≤0.05). In contrast, both the COX inhibitor and KCa channel blockers did not attenuate the cinnamaldehyde induced-increases in CVC relative to the vehicle control site for all concentrations (all P≥0.130). We conclude that in human skin in vivo, NOS plays a role in modulating the regulation of cutaneous vasodilation in response to TRPA1 channel activation with no detectable contributions of COX and KCa channels.
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Silva H. The Vascular Effects of Isolated Isoflavones-A Focus on the Determinants of Blood Pressure Regulation. BIOLOGY 2021; 10:49. [PMID: 33445531 PMCID: PMC7827317 DOI: 10.3390/biology10010049] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/27/2020] [Accepted: 01/02/2021] [Indexed: 02/07/2023]
Abstract
Isoflavones are phytoestrogen compounds with important biological activities, including improvement of cardiovascular health. This activity is most evident in populations with a high isoflavone dietary intake, essentially from soybean-based products. The major isoflavones known to display the most important cardiovascular effects are genistein, daidzein, glycitein, formononetin, and biochanin A, although the closely related metabolite equol is also relevant. Most clinical studies have been focused on the impact of dietary intake or supplementation with mixtures of compounds, with only a few addressing the effect of isolated compounds. This paper reviews the main actions of isolated isoflavones on the vasculature, with particular focus given to their effect on the determinants of blood pressure regulation. Isoflavones exert vasorelaxation due to a multitude of pathways in different vascular beds. They can act in the endothelium to potentiate the release of NO and endothelium-derived hyperpolarization factors. In the vascular smooth muscle, isoflavones modulate calcium and potassium channels, leading to hyperpolarization and relaxation. Some of these effects are influenced by the binding of isoflavones to estrogen receptors and to the inhibition of specific kinase enzymes. The vasorelaxation effects of isoflavones are mostly obtained with plasma concentrations in the micromolar range, which are only attained through supplementation. This paper highlights isolated isoflavones as potentially suitable alternatives to soy-based foodstuffs and supplements and which could enlarge the current therapeutic arsenal. Nonetheless, more studies are needed to better establish their safety profile and elect the most useful applications.
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Affiliation(s)
- Henrique Silva
- Informetrics Research Group, Ton Duc Thang University, Ho Chi Minh City 758307, Vietnam;
- Faculty of Pharmacy, Ton Duc Thang University, Ho Chi Minh City 758307, Vietnam
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7
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Gemae MR, Akerman AP, McGarr GW, Meade RD, Notley SR, Schmidt MD, Rutherford MM, Kenny GP. Myths and methodologies: Reliability of forearm cutaneous vasodilatation measured using laser‐Doppler flowmetry during whole‐body passive heating. Exp Physiol 2020; 106:634-652. [DOI: 10.1113/ep089073] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 11/23/2020] [Indexed: 12/15/2022]
Affiliation(s)
- Mohamed R. Gemae
- Human and Environmental Physiology Research Unit University of Ottawa Ottawa Ontario Canada
| | - Ashley P. Akerman
- 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
| | - Sean R. Notley
- Human and Environmental Physiology Research Unit University of Ottawa Ottawa Ontario Canada
| | - Madison D. Schmidt
- Human and Environmental Physiology Research Unit University of Ottawa Ottawa Ontario Canada
| | - Maura M. Rutherford
- Human and Environmental Physiology Research Unit University of Ottawa Ottawa Ontario Canada
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit University of Ottawa Ottawa Ontario Canada
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8
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Wong BJ, Turner CG, Miller JT, Walker DC, Sebeh Y, Hayat MJ, Otis JS, Quyyumi AA. Sensory nerve-mediated and nitric oxide-dependent cutaneous vasodilation in normotensive and prehypertensive non-Hispanic blacks and whites. Am J Physiol Heart Circ Physiol 2020; 319:H271-H281. [PMID: 32559139 DOI: 10.1152/ajpheart.00177.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The purpose of this study was to investigate the effect of race and subclinical elevations in blood pressure (i.e., prehypertension) on cutaneous sensory nerve-mediated and nitric oxide (NO)-dependent vasodilation. We recruited participants who self-identified as either non-Hispanic black (n = 16) or non-Hispanic white (n = 16). Within each group, participants were subdivided as either normotensive (n = 8 per group) or prehypertensive (n = 8 per group). Each participant was instrumented with four intradermal microdialysis fibers: 1) control (lactated Ringer's), 2) 5% lidocaine (sensory nerve inhibition), 3) 20 mM Nω-nitro-l-arginine methyl ester (l-NAME) (NO synthase inhibition), and 4) lidocaine + l-NAME. Skin blood flow was assessed via laser-Doppler flowmetry, and each site underwent local heating from 33°C to 39°C. At the plateau, 20 mM l-NAME were infused at control and lidocaine sites to quantify NO-dependent vasodilation. Maximal vasodilation was induced via 54 mM sodium nitroprusside and local heating to 43°C. Data are means ± SD. Sensory nerve-mediated cutaneous vasodilation was reduced in prehypertensive non-Hispanic white (34 ± 7%) and both non-Hispanic black groups (normotensive, 20 ± 9%, prehypertensive, 24 ± 15%) relative to normotensive non-Hispanic whites (54 ± 12%). NO-dependent vasodilation was also reduced in prehypertensive non-Hispanic white (41 ± 7%) and both non-Hispanic black groups (normotensive, 44 ± 7%, prehypertensive, 19 ± 7%) relative to normotensive non-Hispanic whites (60 ± 11%). The decrease in NO-dependent vasodilation in prehypertensive non-Hispanic blacks was further reduced relative to all other groups. These data suggest subclinical increases in blood pressure adversely affect sensory-mediated and NO-dependent vasodilation in both non-Hispanic blacks and whites.NEW & NOTEWORTHY Overt hypertension is known to reduce cutaneous sensory nerve-mediated and nitric oxide (NO)-dependent vasodilation, but the effect of subclinical increases in blood pressure (i.e., prehypertension) is unknown. The combined effect of race and prehypertension is also unknown. In this study, we found that prehypertension reduces cutaneous sensory nerve-mediated and NO-dependent vasodilation in both non-Hispanic white and black populations, with the greatest reductions observed in prehypertensive non-Hispanic blacks.
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Affiliation(s)
- Brett J Wong
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Casey G Turner
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - James T Miller
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Demetria C Walker
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Yesser Sebeh
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Matthew J Hayat
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Jeffrey S Otis
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Arshed A Quyyumi
- Emory Clinical Cardiovascular Research Institute, School of Medicine, Emory University, Atlanta, Georgia
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Elawa S, Mirdell R, Farnebo S, Tesselaar E. Skin blood flow response to topically applied methyl nicotinate: Possible mechanisms. Skin Res Technol 2019; 26:343-348. [PMID: 31777124 DOI: 10.1111/srt.12807] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 11/09/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Methyl nicotinate (MN) induces a local cutaneous erythema in the skin and may be valuable as a local provocation in the assessment of microcirculation and skin viability. The mechanisms through which MN mediates its vascular effect are not fully known. The aim of this study was to characterize the vasodilatory effects of topically applied MN and to study the involvement of nitric oxide (NO), local sensory nerves, and prostaglandin-mediated pathways. METHODS MN was applied on the skin of healthy subjects in which NO-mediated (L-NMMA), nerve-mediated (lidocaine/prilocaine), and cyclooxygenase-mediated (NSAID) pathways were selectively inhibited. Microvascular responses in the skin were measured using laser speckle contrast imaging (LSCI). RESULTS NSAID reduced the MN-induced perfusion increase with 82% (P < .01), whereas lidocaine/prilocaine reduced it with 32% (P < .01). L-NMMA did not affect the microvascular response to MN. CONCLUSION The prostaglandin pathway and local sensory nerves are involved in the vasodilatory actions of MN in the skin.
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Affiliation(s)
- Sherif Elawa
- Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden.,Department of Plastic Surgery, Hand Surgery, and Burns, Linköping University, Linköping, Sweden
| | - Robin Mirdell
- Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | - Simon Farnebo
- Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden.,Department of Plastic Surgery, Hand Surgery, and Burns, Linköping University, Linköping, Sweden
| | - Erik Tesselaar
- Department of Medical Radiation Physics, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
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Francisco MA, Minson CT. Cutaneous active vasodilation as a heat loss thermoeffector. HANDBOOK OF CLINICAL NEUROLOGY 2019; 156:193-209. [PMID: 30454590 DOI: 10.1016/b978-0-444-63912-7.00012-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Human skin is the interface between the human body and the environment. As such, human temperature regulation relies largely on cutaneous vasomotor and sudomotor adjustments to appropriately thermoregulate. In particular, changes in skin blood flow can increase or decrease the convective heat transfer from internal tissues to the periphery where it can increase or prevent heat loss to the environment. Thermoregulatory control of the cutaneous vasculature is largely due to cutaneous sympathetic nerves. Sympathetic adrenergic nerves mediate vasoconstriction of the skin, similar to other vascular beds, whereas active vasodilator nerves in nonglabrous skin respond to changes in internal and peripheral temperatures and can profoundly increase skin blood flow. Activation of these vasodilator nerves is known as cutaneous active vasodilation and has been the subject of much recent research. This research has uncovered a highly complex system that involves the activation of multiple receptors and vasodilator pathways in a synergistic and sometimes redundant manner. This complexity and redundancy has left our understanding of cutaneous active vasodilation incomplete; however, the employment of new techniques and use of new pharmacologic agents have introduced many new insights into cutaneous active vasodilation.
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Affiliation(s)
- Michael A Francisco
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Christopher T Minson
- Department of Human Physiology, University of Oregon, Eugene, OR, United States.
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11
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Craighead DH, Alexander LM. Menthol-Induced Cutaneous Vasodilation Is Preserved in Essential Hypertensive Men and Women. Am J Hypertens 2017; 30:1156-1162. [PMID: 28985244 PMCID: PMC5861574 DOI: 10.1093/ajh/hpx127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/23/2017] [Accepted: 07/10/2017] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Menthol is a selective transient receptor potential melastatin 8 (TRPM8) channel agonist that induces cutaneous vasodilation in young, normotensive men and women through nitric oxide synthase (NOS)-, endothelium-derived hyperpolarizing factor (EDHF)-, and sensory nerve-mediated mechanisms. Microvascular dysfunction is present in essential hypertension and whether menthol induces vasodilation is men and women with essential hypertension is equivocal. METHODS Four intradermal microdialysis fibers were placed in the forearm of 9 essential hypertensive and 10 age-matched normotensive control subjects. Sites were pretreated with lactated Ringer's (control), l-NAME (NOS inhibited), TEA (EDHF inhibited), and lidocaine (sensory nerve inhibited). The microdialysis fibers were then perfused with 7 increasing doses of menthol (0.1-500 mM). Red cell flux in response to menthol was measured with laser Doppler flowmetry. Data were normalized to mean arterial pressure and presented as a percentage of site-specific maximum vasodilation (%CVCmax). RESULTS At the control site, menthol caused vasodilation in both the normotensive and hypertensive groups (menthol doses 100, 250, and 500 mM; all P < 0.05 compared to baseline). There were no differences between groups (P = 0.58, main effect). There was no effect of either NOS or sensory nerve inhibition on menthol-induced vasodilation in the normotensive group; however, menthol-induced vasodilation was attenuated with NOS and sensory nerve inhibition in the hypertensive group. EDHF inhibition attenuated menthol-induced vasodilation in both groups. CONCLUSIONS Menthol-induced vasodilation has NO, EDHF, and sensory nerve components. Menthol-induced cutaneous vasodilation is preserved in hypertensive subjects. However, the hypertensive subjects exhibited a loss of redundant vasodilator systems.
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Affiliation(s)
- Daniel H Craighead
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Lacy M Alexander
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania, USA
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12
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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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13
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Amano T, Fujii N, Kenny GP, Inoue Y, Kondo N. Do nitric oxide synthase and cyclooxygenase contribute to sweating response during passive heating in endurance-trained athletes? Physiol Rep 2017; 5:5/17/e13403. [PMID: 28899912 PMCID: PMC5599863 DOI: 10.14814/phy2.13403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 08/08/2017] [Indexed: 11/24/2022] Open
Abstract
The aim of our study was to determine if habitual endurance training can influence the relative contribution of nitric oxide synthase (NOS) and cyclooxygenase (COX) in the regulation of sweating during a passive heat stress in young adults. Ten trained athletes and nine untrained counterparts were passively heated until oral temperature (as estimated by sublingual temperature, Tor) increased by 1.5°C above baseline resting. Forearm sweat rate (ventilated capsule) was measured at three skin sites continuously perfused with either lactated Ringer's solution (Control), 10 mmol/L NG -nitro-L-arginine methyl ester (L-NAME, non-selective NOS inhibitor), or 10 mmol/L ketorolac (Ketorolac, non-selective COX inhibitor) via intradermal microdialysis. Sweat rate was averaged for each 0.3°C increase in Tor Sweat rate at the L-NAME site was lower than Control following a 0.9 and 1.2°C increase in Tor in both groups (all P ≤ 0.05). Relative to the Control site, NOS-inhibition reduced sweating similarly between the groups (P = 0.51). Sweat rate at the Ketorolac site was not different from the Control at any levels of Tor in both groups (P > 0.05). Nevertheless, a greater sweat rate was measured at the end of heating in the trained as compared to the untrained individuals (P ≤ 0.05). We show that NOS contributes similarly to sweating in both trained and untrained individuals during a passive heat stress. Further, no effect of COX on sweating was measured for either group. The greater sweat production observed in endurance-trained athletes is likely mediated by factors other than NOS- and COX-dependent mechanisms.
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Affiliation(s)
- Tatsuro Amano
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Naoto Fujii
- Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit University of Ottawa, Ottawa, Canada
| | - Yoshimitsu Inoue
- Laboratory for Human Performance Research Osaka International University, Osaka, Japan
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology Graduate School of Human Development and Environment Kobe University, Kobe, Japan
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14
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Amano T, Fujii N, Louie JC, Meade RD, Kenny GP. Individual variations in nitric oxide synthase-dependent sweating in young and older males during exercise in the heat: role of aerobic power. Physiol Rep 2017; 5:5/6/e13208. [PMID: 28325791 PMCID: PMC5371569 DOI: 10.14814/phy2.13208] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 02/22/2017] [Indexed: 11/24/2022] Open
Abstract
We evaluated the association between aerobic power (defined by peak oxygen consumption; VO2peak) and the contribution of nitric oxide synthase (NOS) to the sweating response in young and older individuals during exercise in the heat. Data from 44 young (24 ± 1 years) and 48 older (61 ± 2 years) males with mean VO2peak of 47.8 ± 2.4 (range, 28.0–62.3) and 39.1 ± 2.3 (range, 26.4–55.7) mLO2 kg−1 min−1, respectively, were compiled from our prior studies. Participants performed two 15‐ to 30‐min bouts of exercise at a fixed rate of metabolic heat production of 400 or 500 W, each separated by 15–20 min recovery in the heat (35°C, relative humidity of 20%). Forearm sweat rate (ventilated capsule technique) was measured at two skin sites that were continuously and simultaneously administered with lactated Ringers solution (Control) or 10 mmol/L NG‐nitro‐L‐arginine methyl ester (L‐NAME, nonselective NOS inhibitor) via intradermal microdialysis. Sweat rate during the final 5 min of each exercise bout was lower with L‐NAME compared to the Control in both groups (all P < 0.05). The magnitude of the attenuation in sweat rate induced by L‐NAME compared to the Control was not correlated with VO2peak (all P ≥ 0.46) while this attenuation was negatively correlated with the sweat rate at the Control in both groups and in both exercise bouts (all P < 0.01, R ≤ −0.43). These results suggest that NOS‐dependent sweating is not associated with aerobic power per se, while it becomes evident in individuals who produce larger sweat rates during exercise irrespective of age.
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Affiliation(s)
- Tatsuro Amano
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan.,Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - 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
| | - Jeffrey C Louie
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
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15
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Haqani B, Fujii N, Kondo N, Kenny GP. The mechanisms underlying the muscle metaboreflex modulation of sweating and cutaneous blood flow in passively heated humans. Physiol Rep 2017; 5:5/3/e13123. [PMID: 28183862 PMCID: PMC5309575 DOI: 10.14814/phy2.13123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 12/18/2016] [Indexed: 11/24/2022] Open
Abstract
Metaboreceptors can modulate cutaneous blood flow and sweating during heat stress but the mechanisms remain unknown. Fourteen participants (31 ± 13 years) performed 1‐min bout of isometric handgrip (IHG) exercise at 60% of their maximal voluntary contraction followed by a 3‐min occlusion (OCC), each separated by 10 min, initially under low (LHS, to activate sweating without changes in core temperature) and high (HHS, whole‐body heating to a core temperature increase of 1.0°C) heat stress conditions. Cutaneous vascular conductance (CVC) and sweat rate were measured continuously at four forearm skin sites perfused with 1) lactated Ringer's solution (Control), 2) 10 mmol L‐NAME [inhibits nitric oxide synthase (NOS)], 3) 10 mmol Ketorolac [inhibits cyclooxygenase (COX)], or 4) 4 mmol theophylline (THEO; inhibits adenosine receptors). Relative to pre‐IHG levels with Control, NOS inhibition attenuated the metaboreceptor‐mediated increase in sweating under LHS and HHS (P ≤ 0.05), albeit the attenuation was greater under LHS (P ≤ 0.05). In addition, a reduction from baseline was observed with THEO under LHS during OCC (P ≤ 0.05), but not HHS (both P > 0.05). In contrast, CVC was lower than Control with L‐NAME during OCC in HHS (P ≤ 0.05), but not LHS (P > 0.05). We show that metaboreceptor activation modulates CVC via the stimulation of NOS and adenosine receptors, whereas NOS, but not COX or adenosine receptors, contributes to sweating at all levels of heating.
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Affiliation(s)
- Baies Haqani
- 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
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment Kobe University, Kobe, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics University of Ottawa, Ottawa, Canada
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16
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Mechanisms and time course of menthol-induced cutaneous vasodilation. Microvasc Res 2016; 110:43-47. [PMID: 27899298 DOI: 10.1016/j.mvr.2016.11.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/20/2016] [Accepted: 11/22/2016] [Indexed: 11/23/2022]
Abstract
Menthol is a vasoactive compound that is widely used in topical analgesic agents. Menthol induces cutaneous vasodilation, however the underlying mechanisms are unknown. Determining the rates of appearance and clearance of menthol in the skin is important for optimizing topical treatment formulation and dosing. The purpose of this study was to determine the mechanisms contributing to menthol-mediated cutaneous vasodilation and to establish a time course for menthol appearance/clearance in the skin. Ten young (23±1years, 5 males 5 females) subjects participated in two protocols. In study 1, four intradermal microdialysis fibers were perfused with increasing doses of menthol (0.1-500mM) and inhibitors for nitric oxide (NO), endothelium derived hyperpolarizing factors (EDHFs), and sensory nerves. Skin blood flow was measured with laser Doppler flowmetry and normalized to %CVCmax. In study 2, two intradermal microdialysis fibers were perfused with lactated Ringer's solution. 0.017mL·cm-2 of a 4% menthol gel was placed over each fiber. 5μL samples of dialysate from the microdialysis fibers were collected every 30min and analyzed for the presence of menthol with high performance gas chromatography/mass spectrometry. Skin blood flow (laser speckle contrast imaging) and subjective ratings of menthol sensation were simultaneously obtained with dialysate samples. In study 1, menthol induced cutaneous vasodilation at all doses ≥100mM (all p<0.05). However, inhibition of either NO, EDHFs, or sensory nerves fully inhibited menthol-mediated vasodilation (all p>0.05). In study 2, significant menthol was detected in dialysate 30min post menthol application (0.89ng, p=0.0002). Relative to baseline, cutaneous vasodilation was elevated from minutes 15-45 and ratings of menthol sensation were elevated from minute 5-60 post menthol application (all p<0.05). Menthol induces cutaneous vasodilation in the skin through multiple vasodilator pathways, including NO, EDHF, and sensory nerves. Topical menthol is detectable in the skin within 30min and is cleared by 60min. Skin blood flow and perceptual measures follow a similar time course as menthol appearance/clearance.
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17
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Hosaka F, Yamamoto M, Cho KH, Jang HS, Murakami G, Abe SI. Human nasociliary nerve with special reference to its unique parasympathetic cutaneous innervation. Anat Cell Biol 2016; 49:132-7. [PMID: 27382515 PMCID: PMC4927428 DOI: 10.5115/acb.2016.49.2.132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/26/2016] [Accepted: 06/02/2016] [Indexed: 02/08/2023] Open
Abstract
The frontal nerve is characterized by its great content of sympathetic nerve fibers in contrast to cutaneous branches of the maxillary and mandibular nerves. However, we needed to add information about composite fibers of cutaneous branches of the nasociliary nerve. Using cadaveric specimens from 20 donated cadavers (mean age, 85), we performed immunohistochemistry of tyrosine hydroxylase (TH), neuronal nitric oxide synthase (nNOS), and vasoactive intestinal polypeptide (VIP). The nasocilliary nerve contained abundant nNOS-positive fibers in contrast to few TH- and VIP-positive fibers. The short ciliary nerves also contained nNOS-positive fibers, but TH-positive fibers were more numerous than nNOS-positive ones. Parasympathetic innervation to the sweat gland is well known, but the original nerve course seemed not to be demonstrated yet. The present study may be the first report on a skin nerve containing abundant nNOS-positive fibers. The unique parasympathetic contents in the nasocilliary nerve seemed to supply the forehead sweat glands as well as glands in the eyelid and nasal epithelium.
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Affiliation(s)
- Fumio Hosaka
- Division of Ophthalmology, Iwamizawa Municipal Hospital, Iwamizawa, Japan
| | | | - Kwang Ho Cho
- Department of Neurology, Wonkwang University School of Medicine and Hospital, Institute of Wonkwang Medical Science, Iksan, Korea
| | - Hyung Suk Jang
- Division of Physical Therapy, Ongoul Rehabilitation Hospital, Jeonju, Korea
| | - Gen Murakami
- Division of Internal Medicine, Iwamizawa Kojin-kai Hospital, Iwamizawa, Japan
| | - Shin-Ichi Abe
- Department of Anatomy, Tokyo Dental College, Chiba, Japan
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18
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Wong BJ, Hollowed CG. Current concepts of active vasodilation in human skin. Temperature (Austin) 2016; 4:41-59. [PMID: 28349094 PMCID: PMC5356216 DOI: 10.1080/23328940.2016.1200203] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/07/2016] [Accepted: 06/07/2016] [Indexed: 10/30/2022] Open
Abstract
In humans, an increase in internal core temperature elicits large increases in skin blood flow and sweating. The increase in skin blood flow serves to transfer heat via convection from the body core to the skin surface while sweating results in evaporative cooling of the skin. Cutaneous vasodilation and sudomotor activity are controlled by a sympathetic cholinergic active vasodilator system that is hypothesized to operate through a co-transmission mechanism. To date, mechanisms of cutaneous active vasodilation remain equivocal despite many years of research by several productive laboratory groups. The purpose of this review is to highlight recent advancements in the field of cutaneous active vasodilation framed in the context of some of the historical findings that laid the groundwork for our current understanding of cutaneous active vasodilation.
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Affiliation(s)
- Brett J. Wong
- Department of Kinesiology & Health, Georgia State University, Atlanta, GA, USA
| | - Casey G. Hollowed
- Department of Kinesiology & Health, Georgia State University, Atlanta, GA, USA
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Craighead DH, Alexander LM. Topical menthol increases cutaneous blood flow. Microvasc Res 2016; 107:39-45. [PMID: 27131832 DOI: 10.1016/j.mvr.2016.04.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 04/25/2016] [Accepted: 04/26/2016] [Indexed: 10/21/2022]
Abstract
Menthol, the active ingredient in several topically applied analgesics, activates transient receptor potential melastatin 8 (TRPM8) receptors on sensory nerves and on the vasculature inducing a cooling sensation on the skin. Ilex paraguariensis is also a common ingredient in topical analgesics that has potential vasoactive properties and may alter the mechanisms of action of menthol. We sought to characterize the microvascular effects of topical menthol and ilex application and to determine the mechanism(s) through which these compounds may independently and combined alter cutaneous blood flow. We hypothesized that menthol would induce vasoconstriction and that ilex would not alter skin blood flow (SkBF). Three separate protocols were conducted to examine menthol and ilex-mediated changes in SkBF. In protocol 1, placebo, 4% menthol, 0.7% ilex, and combination menthol+ilex gels were applied separately to the skin and red cell flux was continuously measured utilizing laser speckle contrast imaging (LSCI). In protocol 2, seven concentrations of menthol gel (0.04%, 0.4%, 1%, 2%, 4%, 7%, 8%) were applied to the skin to model the dose-response curve. In protocol 3, placebo, menthol, ilex, and menthol+ilex gels were applied to skin under local thermal control (34°C) both with and without sensory nerve blockage (topical lidocaine 4%). Post-occlusive reactive hyperemia (PORH) and local heating (42°C) protocols were conducted to determine the relative contribution of endothelium derived hyperpolarizing factors (EDHFs)/sensory nerves and nitric oxide (NO), respectively. Red cell flux was normalized to mean arterial pressure expressed as cutaneous vascular conductance (CVC: flux·mmHg(-1)) in all protocols. Topical menthol application increased SkBF compared to placebo (3.41±0.33 vs 1.1±0.19CVC: p<0.001). During the dose-response, SkBF increased with increasing doses of menthol (main effect, p<0.05) with an ED50 of 1.0%. Similarly, SkBF was increased after menthol application during PORH (3.62±0.29 vs. 2.50±0.21flux·mmHg(-1); p<0.001), but not local heating (2.98±0.24 vs 2.86±0.32flux·mmHg(-1); p=0.44). Concurrent sensory nerve inhibition attenuated menthol-mediated vasodilation at thermoneutral baseline (1.29±0.19flux·mmHg(-1); p<0.001) and during PORH (2.79±0.28flux·mmHg(-1); p<0.001), but not during local heating (3.45±0.21flux·mmHg(-1); p=0.1). Topically applied menthol, but not ilex, dose-dependently increases blood flow in the cutaneous microvasculature. This increase in blood flow is mediated, in-part by sensory nerves and EDHFs.
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Affiliation(s)
- Daniel H Craighead
- The Pennsylvania State University, University Park, PA 16802, United States
| | - Lacy M Alexander
- The Pennsylvania State University, University Park, PA 16802, United States.
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20
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Carter HH, Spence AL, Atkinson CL, Pugh CJA, Cable NT, Thijssen DHJ, Naylor LH, Green DJ. Distinct effects of blood flow and temperature on cutaneous microvascular adaptation. Med Sci Sports Exerc 2015; 46:2113-21. [PMID: 25338190 DOI: 10.1249/mss.0000000000000349] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE We performed two experiments to determine whether cutaneous microvascular adaptations in response to repeated core temperature (Tc) elevation are mediated by increases in skin blood flow (SkBF) and/or skin temperature. METHODS Healthy subjects participated for 8 wk in thrice-weekly bouts of 30-min lower limb heating (40°C). In study 1, both forearms were "clamped" at basal skin temperature throughout each heating bout (n = 9). Study 2 involved identical lower limb heating, with the forearms under ambient conditions (unclamped, n = 10). In both studies, a cuff was inflated around one forearm during the heating bouts to assess the contribution of SkBF and temperature responses. We assessed forearm SkBF responses to both lower limb (systemic reflex) heating and to local heating of the forearm skin, pre- and postintervention. RESULTS Acutely, lower limb heating increased Tc (study 1, 0.63°C ± 0.15°C; study 2, 0.69°C ± 0.19°C; P < 0.001) and forearm SkBF (study 1, 0.13 ± 0.03 vs 1.52 ± 0.51; study 2, 0.14 ± 0.01 vs 1.17 ± 0.38 cutaneous vascular conductance (CVC); P < 0.001), with skin responses significantly attenuated in the cuffed forearm (P < 0.01). SkBF responses to local heating decreased in study 1 (clamped forearms; week 0 vs week 8, 1.46 ± 0.52 vs 0.99 ± 0.44 CVC; P < 0.05), whereas increases occurred in study 2 (unclamped; week 0 vs week 8, 1.89 ± 0.57 vs 2.27 ± 0.52 CVC; P < 0.05). Cuff placement abolished local adaptations in both studies. CONCLUSIONS Our results indicate that repeated increases in SkBF and skin temperature result in increased skin flux responses to local heating, whereas repeated increases in SkBF in the absence of change in skin temperature induced the opposite response. Repeated increases in Tc induce intrinsic microvascular changes, the nature of which are dependent upon both SkBF and skin temperature.
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Affiliation(s)
- Howard H Carter
- 1School of Sport Science, Exercise and Health, University Of Western Australia, Crawley, Western Australia, AUSTRALIA; 2Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, UNITED KINGDOM; and 3Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The NETHERLANDS
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The contribution of sensory nerves to cutaneous vasodilatation of the forearm and leg to local skin heating. Eur J Appl Physiol 2015; 115:2091-8. [PMID: 25998144 DOI: 10.1007/s00421-015-3188-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 05/09/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE The initial cutaneous vasodilatory response to local skin heating is larger in the forearm than the leg. While the initial vasodilatation of the forearm to local heating is primarily dependent on sensory nerves, their role in the leg is unknown. We compared the contribution of sensory nerves in driving the cutaneous vasodilatory response of the forearm and leg to local heating using local anaesthetic (EMLA) cream. METHOD In seven participants, two skin sites were selected on both the dorsal forearm and anterolateral calf; one site on each region received EMLA, with the other an untreated control. All sites were controlled at 33 °C and then locally heated to 42 °C with integrated laser-Doppler local heating probes. RESULTS Cutaneous vascular conductance (CVC) during the initial vasodilatation to local heating was smaller in the leg (47 ± 9% max) compared to the forearm (62 ± 7 % max) (P = 0.012). EMLA reduced the initial vasodilatation at both the leg (27 ± 13 % max) (P = 0.02) and forearm (33 ± 14% max) (P < 0.001). The times to onset of vasodilatation, initial vasodilatory peak, and plateau phase were longer in the leg compared to the forearm (all P < 0.05), and EMLA increased these times in both regions (both P < 0.05). CVC during the plateau phase to sustained local skin heating was higher in the leg compared to the forearm at both the untreated (93 ± 6 vs. 85 ± 4% max) (P = 0.33) and EMLA-treated (94 ± 5 vs. 86 ± 6% max) (P = 0.001) sites; EMLA did not affect CVC (P > 0.05). CONCLUSION The differences in the initial vasodilatory peak to local skin heating between the forearm and the leg are due to the contribution of sensory nerves.
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22
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Levitt EL, Keen JT, Wong BJ. Augmented reflex cutaneous vasodilatation following short-term dietary nitrate supplementation in humans. Exp Physiol 2015; 100:708-18. [DOI: 10.1113/ep085061] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/30/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Erica L. Levitt
- Department of Kinesiology; Kansas State University; Manhattan KS USA
| | - Jeremy T. Keen
- Department of Kinesiology; Kansas State University; Manhattan KS USA
| | - Brett J. Wong
- Department of Kinesiology; Kansas State University; Manhattan KS USA
- Department of Kinesiology and Health; Georgia State University; Atlanta GA USA
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23
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Fujii N, McGinn R, Halili L, Singh MS, Kondo N, Kenny GP. Cutaneous vascular and sweating responses to intradermal administration of ATP: a role for nitric oxide synthase and cyclooxygenase? J Physiol 2015; 593:2515-25. [PMID: 25809194 DOI: 10.1113/jp270147] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/13/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS In humans in vivo, the mechanisms behind ATP-mediated cutaneous vasodilatation along with whether and how ATP increases sweating remains uncertain. Recent work has implicated nitric oxide synthase (NOS), cyclooxygenase (COX) and/or adenosine in the modulation of cutaneous vasodilatation and sweat production during both local (i.e. localized heating) and whole-body heat stress (i.e. exercise-induced heat stress). We evaluated whether ATP-mediated cutaneous vasodilatation and sweating is mediated via NOS, COX and/or adenosine. We show that in humans in vivo, intradermal administration of ATP induces pronounced vasodilatation which is partially mediated by NOS, but neither COX nor adenosine influences ATP-mediated vasodilatation, and ATP alone does not induce an increase in sweating. These findings advance our basic physiological knowledge regarding control of skin blood flow and sweating, and provide insight into the mechanisms governing thermoeffector activity, which has major implications for whole-body heat exchange and therefore core temperature regulation in humans during heat stress. ABSTRACT In humans in vivo, the mechanisms behind ATP-mediated cutaneous vasodilatation and whether and how ATP increases sweating remain uncertain. We evaluated whether ATP-mediated cutaneous vasodilatation and sweating is mediated via nitric oxide synthase (NOS), cyclooxygenase (COX) and/or adenosine-dependent mechanisms. Cutaneous vascular conductance (CVC, laser Doppler perfusion units/mean arterial pressure) and sweat rate (ventilated capsule) were evaluated at intradermal microdialysis forearm skin sites, each receiving pharmacological agents (two separate protocols). In Protocol 1 (n = 12), sites were perfused with: (1) lactated Ringer solution (Control), (2) 10 mm N(ω) -nitro-l-arginine (l-NNA, a NOS inhibitor), (3) 10 mm ketorolac (Ketorolac, a COX inhibitor) or (4) a combination of 10 mm l-NNA + 10 mm ketorolac (l-NNA + Ketorolac). In Protocol 2 (n = 8), sites were perfused with: (1) lactated Ringer solution (Control) or (2) 4 mm theophylline (Theophylline, an adenosine receptor inhibitor). At all sites, ATP was simultaneously perfused at 0.12, 1.2, 12, 120 and 1200 nm min(-1) (each for 20 min). Relative to CVC at the Control site with ATP infused at 120 nm min(-1) (71 ± 9% of max CVC), CVC at the Ketorolac site was comparable (64 ± 13% of max CVC, P = 0.407), but lower at l-NNA (51 ± 15% of max CVC, P = 0.040) and l-NNA + Ketorolac (51 ± 13% of max CVC, P = 0.049) sites. Conversely, across the four skin sites at any other ATP infusion rate (all P > 0.174), no differences in CVC were observed. Theophylline did not influence CVC at any ATP infusion rate (all P > 0.234). Furthermore, no ATP infusion rate elicited an increase in sweating from baseline at any skin site (all P > 0.235). We show that NOS, but neither COX nor adenosine receptors, modulates ATP-mediated cutaneous vasodilatation, whereas ATP does not directly increase sweating.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Ryan McGinn
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - 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
| | - Narihiko Kondo
- Faculty of Human Development, Kobe University, Kobe, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
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Keen JT, Levitt EL, Hodges GJ, Wong BJ. Short-term dietary nitrate supplementation augments cutaneous vasodilatation and reduces mean arterial pressure in healthy humans. Microvasc Res 2015; 98:48-53. [DOI: 10.1016/j.mvr.2014.12.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 12/18/2014] [Accepted: 12/21/2014] [Indexed: 12/26/2022]
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25
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Del Pozzi AT, Hodges GJ. Comparison of the noradrenergic sympathetic nerve contribution during local skin heating at forearm and leg sites in humans. Eur J Appl Physiol 2015; 115:1155-64. [DOI: 10.1007/s00421-014-3097-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 12/24/2014] [Indexed: 01/08/2023]
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26
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Fujii N, McGinn R, Stapleton JM, Paull G, Meade RD, Kenny GP. Evidence for cyclooxygenase-dependent sweating in young males during intermittent exercise in the heat. J Physiol 2014; 592:5327-39. [PMID: 25326453 PMCID: PMC4262342 DOI: 10.1113/jphysiol.2014.280651] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 10/02/2014] [Indexed: 01/22/2023] Open
Abstract
Our recent work implicated nitric oxide (NO) in the control of sweating during intermittent exercise; however, it is unclear if cyclooxygenase (COX) is also involved. On separate days, ten healthy young (24 ± 4 years) males cycled in the heat (35°C). Two 30 min exercise bouts were performed at either a moderate (400 W, moderate heat load) or high (700 W, high heat load) rate of metabolic heat production and were followed by 20 and 40 min of recovery, respectively. Forearm sweating (ventilated capsule) was evaluated at four skin sites that were continuously perfused via intradermal microdialysis with: (1) lactated Ringer solution (Control), (2) 10 mm ketorolac (a non-selective COX inhibitor), (3) 10 mm N G-nitro-l -arginine methyl ester (l -NAME; a non-selective NO synthase inhibitor) or (4) a combination of 10 mm ketorolac + 10 mm l -NAME. During the last 5 min of the first exercise at moderate heat load, forearm sweating (mg min−1 cm−2) was equivalently reduced with ketorolac (0.54 ± 0.08), l -NAME (0.55 ± 0.07) and ketorolac+l -NAME (0.56 ± 0.08) compared to Control (0.67 ± 0.06) (all P < 0.05). Similar results were obtained for the second exercise at moderate heat load (all P < 0.05). However, forearm sweating was similar between the four sites during exercise at high heat load and during recovery regardless of exercise intensity (all P > 0.05). We show that (1) although both COX and NO modulate forearm sweating during intermittent exercise bouts in the heat at a moderate heat load, the effects are not additive, and (2) the contribution of both enzymes to forearm sweating is less evident during intermittent exercise when the heat load is high and during recovery.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Ryan McGinn
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Jill M Stapleton
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Gabrielle Paull
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
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Charkoudian N, Wallin BG. Sympathetic neural activity to the cardiovascular system: integrator of systemic physiology and interindividual characteristics. Compr Physiol 2014; 4:825-50. [PMID: 24715570 DOI: 10.1002/cphy.c130038] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The sympathetic nervous system is a ubiquitous, integrating controller of myriad physiological functions. In the present article, we review the physiology of sympathetic neural control of cardiovascular function with a focus on integrative mechanisms in humans. Direct measurement of sympathetic neural activity (SNA) in humans can be accomplished using microneurography, most commonly performed in the peroneal (fibular) nerve. In humans, muscle SNA (MSNA) is composed of vasoconstrictor fibers; its best-recognized characteristic is its participation in transient, moment-to-moment control of arterial blood pressure via the arterial baroreflex. This property of MSNA contributes to its typical "bursting" pattern which is strongly linked to the cardiac cycle. Recent evidence suggests that sympathetic neural mechanisms and the baroreflex have important roles in the long term control of blood pressure as well. One of the striking characteristics of MSNA is its large interindividual variability. However, in young, normotensive humans, higher MSNA is not linked to higher blood pressure due to balancing influences of other cardiovascular variables. In men, an inverse relationship between MSNA and cardiac output is a major factor in this balance, whereas in women, beta-adrenergic vasodilation offsets the vasoconstrictor/pressor effects of higher MSNA. As people get older (and in people with hypertension) higher MSNA is more likely to be linked to higher blood pressure. Skin SNA (SSNA) can also be measured in humans, although interpretation of SSNA signals is complicated by multiple types of neurons involved (vasoconstrictor, vasodilator, sudomotor and pilomotor). In addition to blood pressure regulation, the sympathetic nervous system contributes to cardiovascular regulation during numerous other reflexes, including those involved in exercise, thermoregulation, chemoreflex regulation, and responses to mental stress.
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Affiliation(s)
- N Charkoudian
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
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McGinn R, Paull G, Meade RD, Fujii N, Kenny GP. Mechanisms underlying the postexercise baroreceptor-mediated suppression of heat loss. Physiol Rep 2014; 2:2/10/e12168. [PMID: 25293599 PMCID: PMC4254094 DOI: 10.14814/phy2.12168] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Reports indicate that postexercise heat loss is modulated by baroreceptor input; however, the mechanisms remain unknown. We examined the time‐dependent involvement of adenosine receptors, noradrenergic transmitters, and nitric oxide (NO) in modulating baroreceptor‐mediated changes in postexercise heat loss. Eight males performed two 15‐min cycling bouts (85% VO2max) each followed by a 45‐min recovery in the heat (35°C). Lower body positive (LBPP), negative (LBNP), or no (Control) pressure were applied in three separate sessions during the final 30‐min of each recovery. Four microdialysis fibres in the forearm skin were perfused with: (1) lactated Ringer's (Ringer's); (2) 4 mmol·L−1 Theophylline (inhibits adenosine receptors); (3) 10 mmol·L−1 Bretylium (inhibits noradrenergic transmitter release); or (4) 10 mmol·L−1 l‐NAME (inhibits NO synthase). We measured cutaneous vascular conductance (CVC; percentage of maximum) calculated as perfusion units divided by mean arterial pressure, and local sweat rate. Compared to Control, LBPP did not influence CVC at l‐NAME, Theophylline or Bretylium during either recovery (P >0.07); however, CVC at Ringer's was increased by ~5‐8% throughout 30 min of LBPP during Recovery 1 (all P <0.02). In fact, CVC at Ringer's was similar to Theophylline and Bretylium during LBPP. Conversely, LBNP reduced CVC at all microdialysis sites by ~7–10% in the last 15 min of Recovery 2 (all P <0.05). Local sweat rate was similar at all treatment sites as a function of pressure condition (P >0.10). We show that baroreceptor input modulates postexercise CVC to some extent via adenosine receptors, noradrenergic vasoconstriction, and NO whereas no influence was observed for postexercise sweating. To assess the mechanisms of the baroreceptor‐mediated suppression of cutaneous blood flow and sweating postexercise, eight young men performed two 15‐min bouts of cycling at 85% of their VO2max each followed by 45 min of recovery during which positive, negative, or no pressure were applied to the lower limbs. Baroreceptors modulated cutaneous blood flow via nitric oxide (panel B), adenosine receptor (panel C), and noradrenergic vasoconstrictor (panel D) dependent mechanisms. On the other hand, baroreceptors were not shown to modulate postexercise sweating.
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Affiliation(s)
- Ryan McGinn
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Gabrielle Paull
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Robert D Meade
- 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
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
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McGinn R, Fujii N, Swift B, Lamarche DT, Kenny GP. Adenosine receptor inhibition attenuates the suppression of postexercise cutaneous blood flow. J Physiol 2014; 592:2667-78. [PMID: 24687586 DOI: 10.1113/jphysiol.2014.274068] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The time-dependent contributions of active vasodilation (e.g. nitric oxide) and noradrenergic vasoconstriction to the postexercise suppression of cutaneous perfusion despite persistent hyperthermia remain unknown. Moreover, adenosine receptors have been shown to mediate the decrease in cutaneous perfusion following passive heating. We examined the time-dependent modulation of nitric oxide synthase, noradrenergic vasoconstriction and adenosine receptors on postexercise cutaneous perfusion. Eight males performed 15 min of high-intensity (85% VO2 max) cycling followed by 60 min of recovery in temperate ambient conditions (25°C). Four microdialysis probes were inserted into the forearm skin and continuously infused with: (1) lactated Ringer solution (Control); (2) 10 mm N(G)-nitro-l-arginine methyl ester (l-NAME; nitric oxide synthase inhibitor); (3) 10 mm bretylium tosylate (BT; inhibitor of noradrenergic vasoconstriction); or (4) 4 mm theophylline (THEO; adenosine receptor inhibitor). Cutaneous vascular conductance (CVC) was expressed as a percentage of maximum and was calculated as perfusion units (laser Doppler) divided by mean arterial pressure. End-exercise CVC was similar in Control, THEO and BT (P > 0.1), but CVC with l-NAME (39 ± 4%) was lower than Control (59 ± 4%, P < 0.01). At 20 min of recovery, Control CVC (22 ± 3%) returned to baseline levels (19 ± 2%, P = 0.11). Relative to Control, CVC was reduced by l-NAME for the first 10 min of recovery whereas CVC was increased with BT for the first 30 min of recovery (P < 0.03). In contrast, CVC with THEO was elevated throughout the 60 min recovery period (P ≤ 0.01) compared to Control. We show that adenosine receptors appear to have a major role in postexercise cutaneous perfusion whereas nitric oxide synthase and noradrenergic vasoconstriction are involved only earlier during recovery.
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Affiliation(s)
- Ryan McGinn
- 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
| | - Brendan Swift
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Dallon T Lamarche
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
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Del Pozzi AT, Carter SJ, Collins AB, Hodges GJ. The regional differences in the contribution of nitric oxide synthase to skin blood flow at forearm and lower leg sites in response to local skin warming. Microvasc Res 2013. [DOI: 10.1016/j.mvr.2013.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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