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Fujii N, Amano T, Kenny GP, Mündel T, Lei TH, Honda Y, Kondo N, Nishiyasu T. TMEM16A blockers T16Ainh-A01 and benzbromarone do not modulate the regulation of sweating and cutaneous vasodilatation in humans in vivo. Exp Physiol 2022; 107:844-853. [PMID: 35688020 DOI: 10.1113/ep090521] [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: 04/19/2022] [Accepted: 06/07/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Do transmembrane member 16A (TMEM16A) blockers modulate the activation of heat loss responses of sweating and cutaneous vasodilatation? What are the main finding and its importance? Relative to the vehicle control site, TMEM16A blockers T16Ainh-A01 and benzbromarone had no effect on sweat rate or cutaneous vascular conductance during whole-body heating inducing a 1.1 ± 0.1°C increase in core temperature above baseline resting levels. These results suggest that TMEM16A blockers T16Ainh-A01 and benzbromarone do not modulate the regulation of sweating and cutaneous vasodilatation during whole-body heat stress. ABSTRACT Animal and in vitro studies suggest that transmembrane member 16A (TMEM16A), a Ca2+ -activated Cl- channel, contributes to regulating eccrine sweating. However, direct evidence supporting this possibility in humans is lacking. We assessed the hypothesis that TMEM16A blockers attenuate sweating during whole-body heating in humans. Additionally, we assessed the associated changes in the heat loss response of cutaneous vasodilatation to determine if a functional role of TMEM16A may exist. Twelve young (24 ± 2 years) adults (six females) underwent whole-body heating using a water-perfused suit to raise core temperature 1.1 ± 0.1°C above baseline. Sweat rate and cutaneous vascular conductance (normalized to maximal conductance via administration of sodium nitroprusside) were evaluated continuously at four forearm skin sites treated continuously by intradermal microdialysis with (1) lactated Ringer's solution (control), (2) 5% dimethyl sulfoxide (DMSO) serving as a vehicle control, or (3) TMEM16A blockers 1 mM T16Ainh-A01 or 2 mM benzbromarone dissolved in 5% DMSO solution. All drugs were administered continuously via intradermal microdialysis. Whole-body heating increased core temperature progressively and this was paralleled by an increase in sweat rate and cutaneous vascular conductance at all skin sites. However, sweat rate (all P > 0.318) and cutaneous vascular conductance (all P ≥ 0.073) did not differ between the vehicle control site relative to the TMEM16A blocker-treated sites. Collectively, our findings indicate that TMEM16A blockers T16Ainh-A01 and benzbromarone do not modulate the regulation of sweating and cutaneous vasodilatation during whole-body heating in young adults in vivo.
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Affiliation(s)
- Naoto Fujii
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tatsuro Amano
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Toby Mündel
- School of Sport Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - Tze-Huan Lei
- College of Physical Education, Hubei Normal University, Huangshi, China
| | - Yasushi Honda
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
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Patchinsky A, Petitpain N, Gillet P, Angioi-Duprez K, Schmutz JL, Bursztejn AC. Dermatological adverse effects of anti-glaucoma eye drops: a review. J Eur Acad Dermatol Venereol 2022; 36:661-670. [PMID: 35032359 DOI: 10.1111/jdv.17928] [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: 09/03/2020] [Accepted: 11/18/2021] [Indexed: 11/28/2022]
Abstract
Many patients are treated for glaucoma. Like other drugs, anti-glaucoma eye drops may induce dermatological adverse effects. We aim to review the dermatological adverse effects secondary to the active agents in anti-glaucoma eye drops through a literature review. In January 2020, we queried PubMed using the following MeSH terms: glaucoma/drug therapy or glaucoma, open angle/drug therapy cross-referenced with parasympathomimetics/adverse effects or adrenergic agonists/adverse effects or carbonic anhydrase inhibitors/adverse effects or prostaglandins F, synthetic/adverse effects or adrenergic beta antagonists/adverse effects or ophthalmic solutions/adverse effects. The initial search identified 1128 studies, of which 49 were excluded for being in a foreign language, 15 for not involving eye drops, 968 for not focusing on adverse dermatological effects, and 11 for insufficient documentation or redundancy. After adding 38 linked studies, we finally analysed 123 studies. The ocular and periocular dermatological adverse effects of eye drops are contact dermatitis, hyperpigmentation, prostaglandin analogue periorbitopathy, mucous membrane pemphigoid, eyelash depigmentation, skin hypertrichosis, and rare cases of melanoma and skin depigmentation. The reported distant dermatological adverse effects are psoriasis, excessive sweating, lichen planus, alopecia, toxic epidermal necrolysis, erythema multiforme, erythroderma, subacute cutaneous lupus erythematosus, nail pigmentation and bullous pemphigoid. Most of the cutaneous adverse effects of anti-glaucoma eye drops are ocular and periocular and induced by prostaglandin analogues. Distant adverse effects are rare and sometimes questionable but should be kept in mind, especially mucous membrane pemphigoid, which could lead to blindness. The role of preservatives, such as benzalkonium chloride, should also be considered.
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Affiliation(s)
- Alexandra Patchinsky
- Service de Dermatologie, CHRU DE NANCY Brabois, Bâtiment des Spécialités Médicales, rue de Morvan, 54511, Vandœuvre lès Nancy, France
| | - Nadine Petitpain
- Service de Pharmacovigilance, Bâtiment de Biologie Médicale et de Biopathologie, CHRU DE NANCY Brabois, rue de Morvan, 54511, Vandœuvre lès Nancy, France
| | - Pierre Gillet
- Service de Pharmacovigilance, Bâtiment de Biologie Médicale et de Biopathologie, CHRU DE NANCY Brabois, rue de Morvan, 54511, Vandœuvre lès Nancy, France.,Université de Lorraine, CNRS, IMoPA, F-54000, Nancy, France
| | - Karine Angioi-Duprez
- Service d'Ophtalmologie, Hôpital d'Adultes, CHRU DE NANCY Brabois, rue du Morvan, 54511, Vandœuvre lès Nancy, France
| | - Jean Luc Schmutz
- Service de Dermatologie, CHRU DE NANCY Brabois, Bâtiment des Spécialités Médicales, rue de Morvan, 54511, Vandœuvre lès Nancy, France
| | - Anne Claire Bursztejn
- Service de Dermatologie, CHRU DE NANCY Brabois, Bâtiment des Spécialités Médicales, rue de Morvan, 54511, Vandœuvre lès Nancy, France
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The influence of environmental and core temperature on cyclooxygenase and PGE2 in healthy humans. Sci Rep 2021; 11:6531. [PMID: 33753764 PMCID: PMC7985197 DOI: 10.1038/s41598-021-84563-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 01/21/2021] [Indexed: 11/08/2022] Open
Abstract
Whether cyclooxygenase (COX)/prostaglandin E2 (PGE2) thermoregulatory pathways, observed in rodents, present in humans? Participants (n = 9) were exposed to three environments; cold (20 °C), thermoneutral (30 °C) and hot (40 °C) for 120 min. Core (Tc)/skin temperature and thermal perception were recorded every 15 min, with COX/PGE2 concentrations determined at baseline, 60 and 120 min. Linear mixed models identified differences between and within subjects/conditions. Random coefficient models determined relationships between Tc and COX/PGE2. Tc [mean (range)] increased in hot [+ 0.8 (0.4-1.2) °C; p < 0.0001; effect size (ES): 2.9], decreased in cold [- 0.5 (- 0.8 to - 0.2) °C; p < 0.0001; ES 2.6] and was unchanged in thermoneutral [+ 0.1 (- 0.2 to 0.4) °C; p = 0.3502]. A relationship between COX2/PGE2 in cold (p = 0.0012) and cold/thermoneutral [collapsed, condition and time (p = 0.0243)] was seen, with higher PGE2 associated with higher Tc. A within condition relationship between Tc/PGE2 was observed in thermoneutral (p = 0.0202) and cold/thermoneutral [collapsed, condition and time (p = 0.0079)] but not cold (p = 0.0631). The data suggests a thermogenic response of the COX/PGE2 pathway insufficient to defend Tc in cold. Further human in vivo research which manipulates COX/PGE2 bioavailability and participant acclimation/acclimatization are warranted to elucidate the influence of COX/PGE2 on Tc.
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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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Evidence for TRPV4 channel induced skin vasodilatation through NOS, COX, and KCa channel mechanisms with no effect on sweat rate in humans. Eur J Pharmacol 2019; 858:172462. [DOI: 10.1016/j.ejphar.2019.172462] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 12/22/2022]
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Fujii N, Danquah MO, Meade RD, Nishiyasu T, Kenny GP. The effect of exogenous activation of protease-activated receptor 2 on cutaneous vasodilatation and sweating in young males during rest and exercise in the heat. Temperature (Austin) 2018; 5:257-266. [PMID: 30377641 PMCID: PMC6205008 DOI: 10.1080/23328940.2018.1506563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Protease-activated receptor 2 (PAR2) exists in the endothelial cells of skin vessels and eccrine sweat glands. We evaluated the hypothesis that exogeneous activation of PAR2 augments cutaneous vasodilatation and sweating during rest and exercise in the heat. In 10 young males (23 ± 5 y), cutaneous vascular conductance (CVC) and sweat rate were measured at four forearm skin sites treated with either 1) lactated Ringer (Control), 2) 0.05 mM, 3) 0.5 mM, or 4) 5 mM SLIGKV-NH2 (PAR2 agonist). Participants initially rested in a semi-recumbent posture under a normothermic ambient condition (25°C) for ~60 min. Thereafter, ambient temperature was increased to 35°C while the participants rested for an additional 60 min. Participants then performed a 50-min bout of cycling (~55% of their pre-determined peak oxygen uptake) followed by a 30-min recovery period. Administration of 5 mM SLIGKV-NH2 increased cutaneous vascular conductance relative to the Control site during normothermic resting (P ≤ 0.05). However, we showed that relative to the Control site, no effect on CVC was observed for any administered dose of SLIGKV-NH2 (0.05-5 mM) during rest (33-39%max CVC), end-exercise (68-70%max CVC), and postexercise recovery (49-53%max CVC) in the heat (all P > 0.05). There were no differences in sweat rate between the Control and all SLIGKV-NH2-treated sites throughout the protocol (0.21-0.23, 1.20-1.27, and 0.32-0.33 mg∙min-1∙cm-2 for rest, end-exercise, and postexercise in the heat, respectively, all P > 0.05). We show that while exogeneous PAR2 activation induces cutaneous vasodilatation during normothermic rest, it does not influence the cutaneous blood flow and sweating responses during rest, exercise or recovery in the heat.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Mercy O. Danquah
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Robert D. Meade
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
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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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Shichiri H, Yamamoto K, Tokura M, Ishida T, Uda A, Bito T, Nishigori C, Nakagawa T, Hirano T, Yano I, Hirai M. Prostaglandin E 1 reduces the keratinocyte toxicity of sorafenib by maintaining signal transducer and activator of transcription 3 (STAT3) activity and enhancing the cAMP response element binding protein (CREB) activity. Biochem Biophys Res Commun 2017; 485:227-233. [PMID: 28237700 DOI: 10.1016/j.bbrc.2017.02.107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 02/20/2017] [Indexed: 11/25/2022]
Abstract
Hand-foot skin reaction (HFSR) is a common side effect of multiple tyrosine kinase inhibitors (mTKIs). HFSR can necessitate dose reductions or interruption of therapy owing to its negative effect on the quality of life. Therefore, effective use of mTKIs requires measures to prevent HFSR. We evaluated the effect of prostaglandin E1 (PGE1) on HFSR, because PGE1 is already used to treat bed sores and skin ulcers and has established angiogenic and antiproliferative effects in keratinocytes. We found that the pathogenesis of sorafenib-induced HFSR is characterized by a decrease in levels of a phosphorylated signal transducer and activator of transcription 3 (STAT3). We investigated the effect of PGE1 on the sorafenib-mediated reduction in phosphorylated STAT3 levels in HaCaT human epidermal keratinocytes. In cells treated with sorafenib, phosphorylated STAT3 levels decreased in a concentration-dependent manner, and this effect was blocked in cells treated with sorafenib and PGE1. Furthermore, the expression of phosphorylated STAT3, the antiapoptotic proteins myeloid cell leukemia-1 (Mcl-1) and survivin decreased in cells pretreated with an inhibitor of cAMP response element binding protein (CREB). Cell viability increased in cells treated with sorafenib and PGE1 compared with that in cells treated with sorafenib alone, and these effects were not observed in STAT3 knockdown HaCaT cells. Collectively, these findings indicate that PGE1 blocks the inhibitory effects of sorafenib on cell growth by maintaining the activity of STAT3 and enhancing the CREB activity. Therefore, PGE1 might represent an effective treatment for the prevention of sorafenib-induced HFSR.
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Affiliation(s)
- Hiroaki Shichiri
- Division of Pharmaceutics, Department of Internal Related, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Kazuhiro Yamamoto
- Department of Pharmacy, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
| | - Maya Tokura
- Educational Center for Clinical Pharmacy, Kobe Pharmaceutical University, 4-19-1, Motoyamakitamachi, Higashinada-ku, Kobe-shi, Hyogo, 658-8558, Japan
| | - Takahiro Ishida
- R&D Department, Momotani Juntenkan LTD, 1-4-1, Uemachi, Chuo-ku, Osaka, 540-0005, Japan
| | - Atsushi Uda
- Department of Pharmacy, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Toshinori Bito
- Division of Dermatology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Chikako Nishigori
- Division of Dermatology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Tsutomu Nakagawa
- Division of Pharmaceutics, Department of Internal Related, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; Department of Pharmacy, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Takeshi Hirano
- Department of Pharmacy, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Ikuko Yano
- Division of Pharmaceutics, Department of Internal Related, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; Department of Pharmacy, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Midori Hirai
- Division of Pharmaceutics, Department of Internal Related, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; Department of Pharmacy, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
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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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Fujii N, Notley SR, Minson CT, Kenny GP. Administration of prostacyclin modulates cutaneous blood flow but not sweating in young and older males: roles for nitric oxide and calcium-activated potassium channels. J Physiol 2016; 594:6419-6429. [PMID: 27511105 DOI: 10.1113/jp273174] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 08/09/2016] [Indexed: 01/19/2023] Open
Abstract
KEY POINTS In young adults, cyclooxygenase (COX) contributes to the heat loss responses of cutaneous vasodilatation and sweating, and this may be mediated by prostacyclin-induced activation of nitric oxide synthase (NOS) and calcium-activated potassium (KCa) channels. This prostacyclin-induced response may be diminished in older relative to young adults because ageing is known to attenuate COX-dependent heat loss responses. We observed that, although prostacyclin does not mediate sweating in young and older males, it does modulate cutaneous vasodilatation, although the magnitude of increase is similar between groups. We also found that, although NOS and KCa channels contribute to prostacyclin-induced cutaneous vasodilatation in young males, these contributions are diminished in older males. Our findings provide new insight into the mechanisms governing heat loss responses and suggest that the age-related diminished COX-dependent heat loss responses reported in previous studies may be a result of the reduced COX-derived production of prostanoids (e.g., prostacyclin) rather than the decreased sensitivity of prostanoid receptors. ABSTRACT Cyclooxygenase (COX) contributes to the regulation of cutaneous vasodilatation and sweating; however, the mechanism(s) underpinning this response remain unresolved. We hypothesized that prostacyclin (a COX-derived product) may directly mediate cutaneous vasodilatation and sweating through nitric oxide synthase (NOS) and calcium-activated potassium (KCa) channels in young adults. However, these responses would be diminished in older adults because ageing attenuates COX-dependent cutaneous vasodilatation and sweating. In young (25 ± 4 years) and older (60 ± 6 years) males (nine per group), cutaneous vascular conductance (CVC) and sweat rate were evaluated at four intradermal forearm skin sites: (i) control; (ii) 10 mm NG -nitro-l-arginine (l-NNA), a non-specific NOS inhibitor; (iii) 50 mm tetraethylammonium (TEA), a non-specific KCa channel blocker; and (iv) 10 mm l-NNA + 50 mm TEA. All four sites were coadministered with prostacyclin in an incremental manner (0.04, 0.4, 4, 40 and 400 μm each for 25 min). Prostacyclin-induced increases in CVC were similar between groups (all concentrations, P > 0.05). l-NNA and TEA, as well as their combination, lowered CVC in young males at all prostacyclin concentrations (P ≤ 0.05), with the exception of l-NNA at 0.04 μm (P > 0.05). In older males, CVC during prostacyclin administration was not influenced by l-NNA (all concentrations), TEA (4-400 μm) or their combination (400 μm) (P > 0.05). No effect on sweat rate was observed in either group (all concentrations, P > 0.05). We conclude that, although prostacyclin does not mediate sweating, it modulates cutaneous vasodilatation to a similar extent in young and older males. Furthermore, although NOS and KCa channels contribute to the prostacyclin-induced cutaneous vasodilatation in young males, these contributions are diminished in older males.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Sean R Notley
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, Australia
| | | | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada.
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