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Yang P, Feng J, Zhu Y, Hao Y. A Novel Cell Volume Sensor for Real-Time Analysis of Ca 2+-Activated K + Channel. ACS Biomater Sci Eng 2023; 9:5255-5259. [PMID: 37639544 DOI: 10.1021/acsbiomaterials.3c00771] [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] [Indexed: 08/31/2023]
Abstract
Potassium channels play a vital role in cell volume regulation. A cell volume sensor was constructed by integrating regulatory volume decrease (RVD) with quartz-crystal microbalance (QCM) for studying potassium channels and their expression. The sensor successfully monitored the K+ channel's activities during RVD by sensitive and noninvasive means. It showed that Ca2+ activated the K+ channel (KCa) and enhanced the RVD level. The inhibition of blockers on K+ channels exhibited an obvious difference in RVD level between normal and cancerous nasopharyngeal cells, suggesting that the KCa channel contributes a dominant role to the RVD function and provides an approach to identify the activation of various K+ channels.
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Affiliation(s)
- Peihui Yang
- Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, People's Republic of China
| | - Jingwei Feng
- Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, People's Republic of China
| | - Yeyan Zhu
- Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, People's Republic of China
| | - Yan Hao
- Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, People's Republic of China
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Lu Y, Yang ML, Shen AL, Lin S, Peng MZ, Wang TY, Lu ZQ, Wang YL, Peng J, Chu JF. Pharmacodynamic Mechanism of Kuanxiong Aerosol for Vasodilation and Improvement of Myocardial Ischemia. Chin J Integr Med 2022; 28:319-329. [PMID: 34897591 DOI: 10.1007/s11655-021-2882-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2021] [Indexed: 10/19/2022]
Abstract
OBJECTIVE To explore the effect of Kuanxiong Aerosol (KXA) on isoproterenol (ISO)-induced myocardial injury in rat models. METHODS Totally 24 rats were radomly divided into control, ISO, KXA low-dose and high-dose groups according to the randomized block design method, and were administered by intragastric administration for 10 consecutive days, and on the 9th and 10th days, rats were injected with ISO for 2 consecutive days to construct an acute myocardial ischemia model to evaluate the improvement of myocardial ischemia by KXA. In addition, the diastolic effect of KXA on rat thoracic aorta and its regulation of ion channels were tested by in vitro vascular tension test. The influence of KXA on the expression of calcium-CaM-dependent protein kinase II (CaMK II)/extracellular regulated protein kinases (ERK) signaling pathway has also been tested. RESULTS KXA significantly reduced the ISO-induced increase in ST-segment, interventricular septal thickness, cardiac mass index and cardiac tissue pathological changes in rats. Moreover, the relaxation of isolated thoracic arterial rings that had been precontracted using norepinephrine (NE) or potassium chloride (KCl) was increased after KXA treatment in an endothelium-independent manner, and was attenuated by preincubation with verapamil, but not with tetraethylammonium chloride, 4-aminopyridine, glibenclamide, or barium chloride. KXA pretreatment attenuated vasoconstriction induced by CaCl2 in Ca2+-free solutions containing K+ or NE. In addition, KXA pretreatment inhibited accumulation of Ca2+ in A7r5 cells mediated by KCl and NE and significantly decreased p-CaMK II and p-ERK levels. CONCLUSION KXA may inhibit influx and release of calcium and activate the CaMK II/ERK signaling pathway to produce vasodilatory effects, thereby improving myocardial injury.
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Affiliation(s)
- Yan Lu
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Chen Keji Academic Thought Inheritance Studio, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Mei-Ling Yang
- Department of Acupuncture and Moxibustion, Third People's Hospital Affiliated to Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - A-Ling Shen
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Chen Keji Academic Thought Inheritance Studio, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Shan Lin
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Chen Keji Academic Thought Inheritance Studio, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Mei-Zhong Peng
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Chen Keji Academic Thought Inheritance Studio, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Tian-Yi Wang
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Chen Keji Academic Thought Inheritance Studio, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Zhu-Qing Lu
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Chen Keji Academic Thought Inheritance Studio, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Yi-Lian Wang
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Chen Keji Academic Thought Inheritance Studio, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Jun Peng
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Chen Keji Academic Thought Inheritance Studio, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
- Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Jian-Feng Chu
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China.
- Chen Keji Academic Thought Inheritance Studio, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China.
- Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China.
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Amano T, Fujii N, Kenny GP, Okamoto Y, Inoue Y, Kondo N. Effects of TEA-sensitive K + channel blockade on cholinergic and thermal sweating in endurance trained and untrained men. Exp Physiol 2022; 107:441-449. [PMID: 35340063 DOI: 10.1113/ep090251] [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: 11/30/2021] [Accepted: 03/23/2022] [Indexed: 11/08/2022]
Abstract
NEW & NOTEWORTHY What is the central question of this study? Does inhibition of K+ channels modulate the exercise-training-induced augmentation in cholinergic and thermal sweating? What is the main finding and its importance? Iontophoretic administration of tetraethylammonium, a K+ channel blocker, blunted sweating induced by a low dose (0.001%) of cholinergic agent pilocarpine, but not heat-induced sweating. However, no differences in the cholinergic sweating were observed between young endurance trained and untrained men. Thus, while K+ channels play a role in the regulation of eccrine sweating, they do not contribute to the increase in sweating commonly observed in endurance trained adults. Our findings provide important new insights into the mechanisms underlying the regulation of sweating by endurance conditioning. ABSTRACT We evaluated the hypothesis that the activation of K+ channels mediate the exercise-training-induced augmentation in cholinergic and thermal sweating. On separate days, 11 endurance trained and 10 untrained men participated in two experimental protocols. Prior to each protocol, we administered 2% tetraethylammonium (TEA, K+ channels blocker) and saline (Control) at forearm skin sites on both arms via transdermal iontophoresis. In protocol 1, a low (0.001%) and high (1%) doses of pilocarpine was administered at the TEA-treated and Control sites over a 60-min period. In protocol 2, participants were passively heated by immersing their lower limbs in hot water (43°C) until core (rectal) temperature (Tco ) increased by 0.8°C above resting levels. Administration of TEA attenuated cholinergic sweating (P = 0.001) during the initial 20-min after the treatment of low dose of pilocarpine only whilst the response was similar between the groups (P = 0.163). Cholinergic and thermal sweating were higher in trained relative to the untrained men (all P≤0.033). Thermal sweating reached ∼90% of the response at a Tco elevation of 0.8°C during initial 20-min of passive heating, which corresponds to the period wherein TEA attenuated cholinergic sweating in protocol 1. However, sweating did not differ between the Control and TEA sites in either group (P = 0.704). We showed that activation of K+ channels does not appear to mediate the elevated sweating response induced by a low dose of pilocarpine in trained men. We also demonstrated that K+ channels do not contribute to sweating during heat stress in either group. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Tatsuro Amano
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Naoto Fujii
- 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
| | - Yumi Okamoto
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - 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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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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Al-Karagholi MAM, Ghanizada H, Nielsen CAW, Ansari A, Gram C, Younis S, Vestergaard MB, Larsson HB, Skovgaard LT, Amin FM, Ashina M. Cerebrovascular effects of glibenclamide investigated using high-resolution magnetic resonance imaging in healthy volunteers. J Cereb Blood Flow Metab 2021; 41:1328-1337. [PMID: 33028147 PMCID: PMC8142144 DOI: 10.1177/0271678x20959294] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Glibenclamide inhibits sulfonylurea receptor (SUR), which regulates several ion channels including SUR1-transient receptor potential melastatin 4 (SUR1-TRPM4) channel and ATP-sensitive potassium (KATP) channel. Stroke upregulates SURl-TRPM4 channel, which causes a rapid edema formation and brain swelling. Glibenclamide may antagonize the formation of cerebral edema during stroke. Preclinical studies showed that glibenclamide inhibits KATP channel-induced vasodilation without altering the basal vascular tone. The in vivo human cerebrovascular effects of glibenclamide have not previously been investigated.In a randomized, double-blind, placebo-controlled, three-way cross-over study, we used advanced 3 T MRI methods to investigate the effects of glibenclamide and KATP channel opener levcromakalim on mean global cerebral blood flow (CBF) and intra- and extracranial artery circumferences in 15 healthy volunteers. Glibenclamide administration did not alter the mean global CBF and the basal vascular tone. Following levcromakalim infusion, we observed a 14% increase of the mean global CBF and an 8% increase of middle cerebral artery (MCA) circumference, and glibenclamide did not attenuate levcromakalim-induced vascular changes. Collectively, the findings demonstrate the vital role of KATP channels in cerebrovascular hemodynamic and indicate that glibenclamide does not inhibit the protective effects of KATP channel activation during hypoxia and ischemia-induced brain injury.
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Affiliation(s)
- Mohammad Al-Mahdi Al-Karagholi
- Department of Neurology, Faculty of Health and Medical Sciences, Danish Headache Center, University of Copenhagen, Rigshospitalet Glostrup, Denmark
| | - Hashmat Ghanizada
- Department of Neurology, Faculty of Health and Medical Sciences, Danish Headache Center, University of Copenhagen, Rigshospitalet Glostrup, Denmark
| | - Cherie Amalie Waldorff Nielsen
- Department of Neurology, Faculty of Health and Medical Sciences, Danish Headache Center, University of Copenhagen, Rigshospitalet Glostrup, Denmark
| | - Assan Ansari
- Department of Neurology, Faculty of Health and Medical Sciences, Danish Headache Center, University of Copenhagen, Rigshospitalet Glostrup, Denmark
| | - Christian Gram
- Department of Neurology, Faculty of Health and Medical Sciences, Danish Headache Center, University of Copenhagen, Rigshospitalet Glostrup, Denmark
| | - Samaria Younis
- Department of Neurology, Faculty of Health and Medical Sciences, Danish Headache Center, University of Copenhagen, Rigshospitalet Glostrup, Denmark
| | - Mark B Vestergaard
- Functional Imaging Unit, Faculty of Health and Medical Sciences, Department of Clinical Physiology, Nuclear Medicine and PET, University of Copenhagen, Rigshospitalet, Denmark
| | - Henrik Bw Larsson
- Functional Imaging Unit, Faculty of Health and Medical Sciences, Department of Clinical Physiology, Nuclear Medicine and PET, University of Copenhagen, Rigshospitalet, Denmark
| | - Lene Theil Skovgaard
- Department of Biostatistics, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Faisal Mohammad Amin
- Department of Neurology, Faculty of Health and Medical Sciences, Danish Headache Center, University of Copenhagen, Rigshospitalet Glostrup, Denmark
| | - Messoud Ashina
- Department of Neurology, Faculty of Health and Medical Sciences, Danish Headache Center, University of Copenhagen, Rigshospitalet Glostrup, Denmark.,Danish Headache Knowledge Center, Rigshospitalet, Glostrup, Denmark
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McGarr GW, Muia CM, Saci S, Fujii N, Kenny GP. K Ca channels are major contributors to ATP-induced cutaneous vasodilation in healthy older adults. Microvasc Res 2020; 133:104096. [PMID: 33058899 DOI: 10.1016/j.mvr.2020.104096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 08/30/2020] [Accepted: 10/08/2020] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To examine the contributions of calcium-activated K+ (KCa) channels and nitric oxide synthase (NOS) to adenosine triphosphate (ATP)-induced cutaneous vasodilation in healthy older adults. METHODS In eleven older adults (69 ± 2 years, 5 females), cutaneous vascular conductance, normalized to maximum vasodilation (%CVCmax) was assessed at four dorsal forearm skin sites that were continuously perfused with either 1) lactated Ringer solution (Control), 2) 50 mM tetraethylammonium (TEA, KCa channel blocker), 3) 10 mM Nω-nitro-L-arginine (L-NNA, NOS inhibitor), or 4) combined 50 mM TEA +10 mM L-NNA, via microdialysis. Local skin temperature was fixed at 33 °C at all sites with local heaters throughout the protocol while the cutaneous vasodilator response was assessed during coadministration of ATP (0.03, 0.3, 3, 30, 300 mM; 20 min per dose), followed by 50 mM sodium nitroprusside and local skin heating to 43 °C to achieve maximum vasodilation (20-30 min). RESULTS Blockade of KCa channels blunted %CVCmax relative to Control from 0.3 to 300 mM ATP (All P < 0.05). A similar response was observed for the combined KCa channel blockade and NOS inhibition site from 3 to 300 mM ATP (All P < 0.05). Conversely, NOS inhibition alone did not influence %CVCmax across all ATP doses (All P > 0.05). CONCLUSION In healthy older adults, KCa channels play an important role in modulating ATP-induced cutaneous vasodilation, while the NOS contribution to this response is negligible.
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Affiliation(s)
- Gregory W McGarr
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Caroline M Muia
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Samah Saci
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada; Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada.
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Al-Karagholi MAM, Ghanizada H, Kokoti L, Paulsen JS, Hansen JM, Ashina M. Effect of K ATP channel blocker glibenclamide on levcromakalim-induced headache. Cephalalgia 2020; 40:1045-1054. [PMID: 32806954 DOI: 10.1177/0333102420949863] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Administration of ATP-sensitive potassium channel opener levcromakalim triggers headache in healthy volunteers and migraine attacks in migraine patients. Here, we investigated the effect of ATP-sensitive potassium channel blocker glibenclamide on levcromakalim-induced headache in healthy volunteers. METHODS In a randomized, double-blind, placebo-controlled, three-way cross-over study, 15 healthy volunteers aged 18-40 years were randomly allocated to receive glibenclamide and levcromakalim (day 1), glibenclamide and placebo (day 2), and placebo and placebo (day 3) on three different days separated by at least 1 week. The primary endpoints were the difference in incidence of headache and the difference in area under the curve for headache intensity scores (0-12 hours) between the days. RESULTS Fifteen healthy volunteers completed the 3 days of the study. More participants (12/15, 80%) developed headache on the glibenclamide-levcromakalim day compared to the glibenclamide-placebo day (5/15, 33%) (p = 0.01; mean difference 47%; 95% confidence interval 18-75%) and compared to the placebo-placebo day (1/15, 7%) (p = 0.001; mean difference 73%; 95% confidence interval 48-99%). We found no difference in headache incidence between glibenclamide-placebo day and placebo-placebo day (p = 0.12; mean difference 27%; 95% confidence interval 1.3-52%). The area under the curve for headache intensity was significantly larger on the glibenclamide-levcromakalim day compared to the glibenclamide-placebo day (p = 0.003); and compared to the placebo-placebo day (p = 0.001). We found no difference in the area under the curve between the glibenclamide-placebo day compared to the placebo-placebo day (p = 0.07). The median time to onset for headache after levcromakalim infusion with glibenclamide pretreatment was delayed (180 min) compared to levcromakalim without pretreatment (30 min) from a previously published study. CONCLUSION Glibenclamide administration did not cause headache, and glibenclamide pretreatment did not prevent levcromakalim-induced headache. However, glibenclamide delayed the onset of levcromakalim-induced headache. More selective blockers are needed to further elucidate the role of the ATP-sensitive potassium channel in headache initiation.Trial Registration: ClinicalTrials.gov NCT03886922.
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Affiliation(s)
- Mohammad Al-Mahdi Al-Karagholi
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Hashmat Ghanizada
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Lili Kokoti
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Joachim S Paulsen
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Jakob Møller Hansen
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark.,Danish Headache Knowledge Center, Rigshospitalet Glostrup, Glostrup, Denmark
| | - Messoud Ashina
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark.,Danish Headache Knowledge Center, Rigshospitalet Glostrup, Glostrup, Denmark
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Abstract
The mechanism by which nitric oxide synthase (NOS) inhibition impacts human sweating is unknown. We tested the hypothesis that the activation of NOS and release on nitric oxide acts to open K+ channels and enhance sweat gland output. Local sweat rate (LSR) was measured with a small sweat capsule mounted on the skin while sweating was initiated by intradermal electrical stimulation. Sigmoid shape stimulus-response curves were generated by plotting the area under the LSR-time curve (LSR AUC) versus log10 stimulus frequency and normalized to the peak AUC response during control trials. NOS inhibition alone reduced the peak sweat rate response to 81.5 ± 4.5% peak LSR AUC of that seen with lactated Ringer's (P = 0.0004). Fifty mM of tetraethylammonium chloride (TEA) alone reduced peak LSR (0.317 ± 0.060 vs. 0.511 ± 0.104 mg·min-1·cm-2, P = 0.03) and the peak LSR AUC response from 0.193 ± 0.170 to 0.158 ± 0.127 mg·cm-2 (P = 0.004). Delivery of a 20 mM nitro-l-arginine methyl ester (l-NAME) following 50 mM TEA produced a further decrease in the peak LSR AUC response to 0.095 ± 0.064 mg·cm-2 (≈20% reduction, P = 0.0145). These data support the hypothesis that sudomotor control of sweat gland activity is locally modulated by a functioning NOS system that appears to be additive and independent to the effect of blockade of K+ channels with TEA.NEW & NOTEWORTHY The contribution of nitric oxide synthase (NOS) to the process of cholinergic-mediated human eccrine sweat production is unclear. Using a novel model for cholinergic-mediated sweating in humans, I demonstrate that blocking the NOS system led to a reduction in local sweat rate (LSR). This reduction in LSR was maintained in the presence of K+ channel blockade with tetraethylammonium.
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Affiliation(s)
- Gary W Mack
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
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10
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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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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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12
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Tan CCS, Chin LKK, Low ICC. Thermoregulation in the Aging Population and Practical Strategies to Overcome a Warmer Tomorrow. Proteomics 2019; 20:e1800468. [PMID: 31652021 DOI: 10.1002/pmic.201800468] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 09/05/2019] [Indexed: 12/11/2022]
Abstract
As global temperatures continue to rise, improving thermal tolerance in the aged population is crucial to counteract age-associated impairments in thermoregulatory function. Impairments in reflex cutaneous vasodilation and sweating response can augment the vulnerability of older adults to heat-related injuries following exposure to heat stress. Mechanisms underlying a compromised cutaneous vasodilation are suggested to include reduced sympathetic neural drive, diminished cholinergic co-transmitter contribution, and altered second messenger signaling events. On the other hand, impairments in sweating response are ascribed to reduced sweat gland cholinergic sensitivity and altered cyclooxygenase and nitric oxide signaling. Several practical mitigation strategies such as exercise, passive heating, and behavioral adaptations are proposed as means to overcome heat stress and improve thermal tolerance in the aged. Aerobic exercise training is shown to be amongst the most effective ways to enhance thermoregulatory function. However, in elderly with limited exercise capability due to chronic diseases and mobility issues, passive heating can serve as a functional alternative as it has been shown to confer similar benefits to that of exercise training. Supplementary to exercise training and passive heating, behavioral adaptations can be applied to further enhance the heat-preparedness of the aged.
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Affiliation(s)
- Chee Chong Shawn Tan
- Department of Physiology, Yong Loo Lin School of Medicine (YLLSoM), National University of Singapore (NUS), Singapore, 117593, Singapore
| | - Li Kang Karen Chin
- Department of Physiology, Yong Loo Lin School of Medicine (YLLSoM), National University of Singapore (NUS), Singapore, 117593, Singapore
| | - Ivan Cherh Chiet Low
- Department of Physiology, Yong Loo Lin School of Medicine (YLLSoM), National University of Singapore (NUS), Singapore, 117593, Singapore
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13
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Al-Karagholi MAM, Sode M, Gozalov A, Ashina M. The vascular effect of glibenclamide: A systematic review. CEPHALALGIA REPORTS 2019. [DOI: 10.1177/2515816319884937] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Objective: To systematically review the vascular effects of glibenclamide. Background: Infusion of adenosine triphosphate (ATP)-sensitive potassium (KATP) channel opener (KCO) levcromakalim dilates cranial arteries and induces headache and migraine attacks. Recent data show that levcromakalim-induced vasodilation is associated with headache. Glibenclamide is a KATP channel blocker that may alter the vascular tone and thus has an impact on headache or migraine prevention. Methods: A search through PubMed was undertaken for studies investigating the vascular effects of glibenclamide in vitro as well as in vivo published until July 2019. Results: We identified 58 articles; 31 in vitro studies, 24 in vivo studies and 3 studies with both. The main findings were that glibenclamide inhibited levcromakalim-induced and other KCOs-induced vasodilation, while the basal vascular tone remained unchanged. Conclusion: Glibenclamide could inhibit vasodilation by KCOs, and further studies are needed to clarify the vascular effect of glibenclamide on human cranial arteries.
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Affiliation(s)
- Mohammad Al-Mahdi Al-Karagholi
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Michael Sode
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Aydin Gozalov
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Messoud Ashina
- Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
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14
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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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15
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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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16
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McGarr GW, Fujii N, Muia CM, Nishiyasu T, Kenny GP. Separate and combined effects of K Ca and K ATP channel blockade with NOS inhibition on cutaneous vasodilation and sweating in older men during heat stress. Am J Physiol Regul Integr Comp Physiol 2019; 317:R113-R120. [PMID: 31091157 DOI: 10.1152/ajpregu.00075.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our objective in this study was to examine the separate and combined effects of potassium (K+) channels and nitric oxide synthase (NOS) on cutaneous vasodilation and sweating in older men during rest and exercise in the heat. In 13 habitually active men (61 ± 4 yr), cutaneous vascular conductance and local sweat rate were assessed at six dorsal forearm skin sites continuously perfused with either 1) lactated Ringer (control), 2) 10 mM NG-nitro-l-arginine methyl ester (l-NAME, NOS inhibitor), 3) 50 mM tetraethylammonium (TEA; Ca2+-activated K+ channel blocker), 4) 5 mM glybenclamide (GLY; ATP-sensitive K+ channel blocker), 5) 50 mM TEA + 10 mM l-NAME, and 6) 5 mM GLY + 10 mM l-NAME via microdialysis. Participants rested in non-heat stress (25°C) and heat stress (35°C) conditions for ∼60 min each, followed by 50 min of moderate-intensity cycling (∼55% V̇o2peak) and 30 min of recovery in the heat. During rest and exercise in the heat, l-NAME, TEA + l-NAME, and GLY + l-NAME attenuated CVC relative to control (all P ≤ 0.05), although l-NAME was not different from TEA + l-NAME or GLY + l-NAME (all P > 0.05). TEA attenuated CVC during rest, whereas GLY attenuated CVC during exercise (both P ≤ 0.05). Additionally, whereas neither l-NAME nor TEA altered sweating throughout the protocol (all P > 0.05), combined TEA + l-NAME attenuated sweating during exercise in the heat (P ≤ 0.05). We conclude that in habitually active older men blockade of KCa and KATP channels attenuates cutaneous vasodilation during rest and exercise in the heat, respectively, and these effects are NOS dependent. Furthermore, combined NOS inhibition and KCa channel blockade attenuates sweating during exercise in the heat.
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Affiliation(s)
- Gregory W McGarr
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa , Ottawa, Ontario , Canada
| | - Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa , Ottawa, Ontario , Canada.,Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba City , Japan
| | - Caroline M Muia
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa , Ottawa, Ontario , Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba City , Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa , Ottawa, Ontario , Canada
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17
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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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18
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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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19
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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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20
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Tucker MA, Six A, Moyen NE, Satterfield AZ, Ganio MS. Effect of hypohydration on postsynaptic cutaneous vasodilation and sweating in healthy men. Am J Physiol Regul Integr Comp Physiol 2017; 312:R637-R642. [DOI: 10.1152/ajpregu.00525.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/23/2017] [Accepted: 02/09/2017] [Indexed: 02/05/2023]
Abstract
Hypohydration decreases cutaneous vasodilation and sweating during heat stress, but it is unknown if these decrements are from postsynaptic (i.e., sweat gland/blood vessel) alterations. The purpose of this study was to determine if hypohydration affects postsynaptic cutaneous vasodilation and sweating responses. Twelve healthy men participated in euhydrated (EU) and hypohydrated (HY) trials, with hypohydration induced via fluid restriction and passive heat stress. Changes in cutaneous vascular conductance (CVC; %max) in response to incremental intradermal infusion of the endothelium-independent vasodilator sodium nitroprusside (SNP) and the endothelium-dependent vasodilator methacholine chloride (MCh) were assessed by laser Doppler flowmetry. Local sweat rate (LSR) was simultaneously assessed at the MCh site via ventilated capsule. At the end of the last dose, maximal CVC was elicited by delivering a maximal dose of SNP (5 × 10−2 M) for 30 min to both sites with simultaneous local heating (~44°C) at the SNP site. The concentration of drug needed to elicit 50% of the maximal response (log EC50) was compared between hydration conditions. The percent body mass loss was greater with HY vs. EU (−2.2 ± 0.7 vs. −0.1 ± 0.7%, P < 0.001). Log EC50 of endothelium-dependent CVC was lower with EU (−3.62 ± 0.22) vs. HY (−2.93 ± 0.08; P = 0.044). Hypohydration did not significantly alter endothelium-independent CVC or LSR (both P > 0.05). In conclusion, hypohydration attenuated endothelium-dependent CVC but did not affect endothelium-independent CVC or LSR responses. These data suggest that reductions in skin blood flow accompanying hypohydration can be partially attributed to altered postsynaptic function.
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Affiliation(s)
- Matthew A. Tucker
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
| | - Ashley Six
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
| | - Nicole E. Moyen
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
- Fitbit, San Francisco, California
| | - Alf Z. Satterfield
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
| | - Matthew S. Ganio
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
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21
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Fujii N, Louie JC, McNeely BD, Amano T, Nishiyasu T, Kenny GP. Mechanisms of nicotine-induced cutaneous vasodilation and sweating in young adults: roles for K Ca, K ATP, and K V channels, nitric oxide, and prostanoids. Appl Physiol Nutr Metab 2017; 42:470-478. [PMID: 28177721 DOI: 10.1139/apnm-2016-0615] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We evaluated the influence of K+ channels (i.e., Ca2+-activated K+ (KCa), ATP-sensitive K+ (KATP), and voltage-gated K+ (KV) channels) and key enzymes (nitric oxide synthase (NOS) and cyclooxygenase (COX)) on nicotine-induced cutaneous vasodilation and sweating. Using intradermal microdialysis, we evaluated forearm cutaneous vascular conductance (CVC) and sweat rate in 2 separate protocols. In protocol 1 (n = 10), 4 separate sites were infused with (i) lactated Ringer (Control), (ii) 50 mmol·L-1 tetraethylammonium (KCa channel blocker), (iii) 5 mmol·L-1 glybenclamide (KATP channel blocker), and (iv) 10 mmol·L-1 4-aminopyridine (KV channel blocker). In protocol 2 (n = 10), 4 sites were infused with (i) lactated Ringer (Control), (ii) 10 mmol·L-1 Nω-nitro-l-arginine (NOS inhibitor), (iii) 10 mmol·L-1 ketorolac (COX inhibitor), or (iv) a combination of NOS+COX inhibitors. At all sites, nicotine was infused in a dose-dependent manner (1.2, 3.6, 11, 33, and 100 mmol·L-1; each for 25 min). Nicotine-induced increase in CVC was attenuated by the KCa, KATP, and KV channel blockers, whereas nicotine-induced increase in sweat rate was reduced by the KCa and KV channel blockers (P ≤ 0.05). COX inhibitor augmented nicotine-induced increase in CVC (P ≤ 0.05), which was absent when NOS inhibitor was co-administered (P > 0.05). In addition, our secondrary experiment (n = 7) demonstrated that muscarinic receptor blockade with 58 μmol·L-1 atropine sulfate salt monohydrate abolished nicotine-induced increases in CVC (1.2-11 mmol·L-1) and sweating (all doses). We show that under a normothermic resting state: (i) KCa, KATP, and KV channels contribute to nicotinic cutaneous vasodilation, (ii) inhibition of COX augments nicotinic cutaneous vasodilation likely through NOS-dependent mechanism(s), and (iii) KCa and KV channels contribute to nicotinic sweating.
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Affiliation(s)
- Naoto Fujii
- a Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Jeffrey C Louie
- a Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Brendan D McNeely
- a Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Tatsuro Amano
- b Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Japan
| | - Takeshi Nishiyasu
- c Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan
| | - Glen P Kenny
- a Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
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22
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Louie JC, Fujii N, Meade RD, McNeely BD, Kenny GP. The roles of K Ca, K ATP, and K V channels in regulating cutaneous vasodilation and sweating during exercise in the heat. Am J Physiol Regul Integr Comp Physiol 2017; 312:R821-R827. [PMID: 28254750 DOI: 10.1152/ajpregu.00507.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/13/2017] [Accepted: 02/28/2017] [Indexed: 01/11/2023]
Abstract
We recently showed the varying roles of Ca2+-activated (KCa), ATP-sensitive (KATP), and voltage-gated (KV) K+ channels in regulating cholinergic cutaneous vasodilation and sweating in normothermic conditions. However, it is unclear whether the respective contributions of these K+ channels remain intact during dynamic exercise in the heat. Eleven young (23 ± 4 yr) men completed a 30-min exercise bout at a fixed rate of metabolic heat production (400 W) followed by a 40-min recovery period in the heat (35°C, 20% relative humidity). Cutaneous vascular conductance (CVC) and local sweat rate were assessed at four forearm skin sites perfused via intradermal microdialysis with: 1) lactated Ringer solution (control); 2) 50 mM tetraethylammonium (nonspecific KCa channel blocker); 3) 5 mM glybenclamide (selective KATP channel blocker); or 4) 10 mM 4-aminopyridine (nonspecific KV channel blocker). Responses were compared at baseline and at 10-min intervals during and following exercise. KCa channel inhibition resulted in greater CVC versus control at end exercise (P = 0.04) and 10 and 20 min into recovery (both P < 0.01). KATP channel blockade attenuated CVC compared with control during baseline (P = 0.04), exercise (all P ≤ 0.04), and 10 min into recovery (P = 0.02). No differences in CVC were observed with KV channel inhibition during baseline (P = 0.15), exercise (all P ≥ 0.06), or recovery (all P ≥ 0.14). With the exception of KV channel inhibition augmenting sweating during baseline (P = 0.04), responses were similar to control with all K+ channel blockers during each time period (all P ≥ 0.07). We demonstrated that KCa and KATP channels contribute to the regulation of cutaneous vasodilation during rest and/or exercise and recovery in the heat.
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Affiliation(s)
- Jeffrey C Louie
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada; and
| | - Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada; and.,Institute of Health and Sports Sciences, University of Tsukuba, Tsukuba, Japan
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada; and
| | - Brendan D McNeely
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada; and
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada; and
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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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