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Hu XQ, Zhang L. Role of transient receptor potential channels in the regulation of vascular tone. Drug Discov Today 2024; 29:104051. [PMID: 38838960 DOI: 10.1016/j.drudis.2024.104051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 05/17/2024] [Accepted: 05/29/2024] [Indexed: 06/07/2024]
Abstract
Vascular tone is a major element in the control of hemodynamics. Transient receptor potential (TRP) channels conducting monovalent and/or divalent cations (e.g. Na+ and Ca2+) are expressed in the vasculature. Accumulating evidence suggests that TRP channels participate in regulating vascular tone by regulating intracellular Ca2+ signaling in both vascular smooth muscle cells (VSMCs) and endothelial cells (ECs). Aberrant expression/function of TRP channels in the vasculature is associated with vascular dysfunction in systemic/pulmonary hypertension and metabolic syndromes. This review intends to summarize our current knowledge of TRP-mediated regulation of vascular tone in both physiological and pathophysiological conditions and to discuss potential therapeutic approaches to tackle abnormal vascular tone due to TRP dysfunction.
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Affiliation(s)
- Xiang-Qun Hu
- Lawrence D. Longo MD Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.
| | - Lubo Zhang
- Lawrence D. Longo MD Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.
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Zizzo MG, Cicio A, Bruno M, Serio R. Inhibitory effect and underlying mechanism of essential oil of Prangos ferulacea Lindl (L.) on spontaneous and induced uterine contractions in non-pregnant rats. Biomed Pharmacother 2023; 167:115570. [PMID: 37757498 DOI: 10.1016/j.biopha.2023.115570] [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: 07/14/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023] Open
Abstract
Evidence suggests the use of natural compounds as support in the management of uterine contractility disorders. We recently demonstrated that the essential oil of Apiacea Prangos ferulacea (L.) (Prangoil) modulates intestinal smooth muscle contractility. Thus, we aimed to evaluate if Prangoil could also affect the contractility of uterine muscle in non-pregnant rat and to investigate the related action mechanism/s. The effects of the aromatic monoterpenes, β-ocimene and carvacrol, constituents of Prangoil, were also evaluated. Spontaneous contractions and contraction-induced by K+-depolarization and oxytocin in rat uterus were recorded in vitro, using organ bath technique. Prangoil reduced the amplitude of spontaneous contractions as well as responses to KCl and oxytocin. β-ocimene and carvacrol matched oil inhibitory effects. Prangoil effects were not affected by nitrergic and adenylyl cyclase inhibitors or non-specific potassium channel blocker, but they were reduced by nifedipine, L-type calcium channel inhibitor, or 2-aminoethoxydiphenylborate (2-APB), membrane-permeant inositol 1,4,5-triphosphate receptor inhibitor. The response to β-ocimene was reduced by nifedipine and by 2-APB (20 μM), whilst carvacrol inhibitory effect was attenuated only by nifedipine. In conclusion, Prangoil, and its components, β-ocimene and carvacrol, reduced spontaneous and KCl or oxytocin-induced contractions of rat myometrium, mainly modulating extracellular Ca2+ influx through L-Type channels and Ca2+ release from the intracellular store. Further studies could contribute to evaluate the potential use of Prangoil against disorders characterized by abnormal uterine contractions.
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Affiliation(s)
- Maria Grazia Zizzo
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, 90128 Palermo, Italy; ATeN (Advanced Technologies Network) Center, Viale delle Scienze, University of Palermo, 90128 Palermo, Italy.
| | - Adele Cicio
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | - Maurizio Bruno
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | - Rosa Serio
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, 90128 Palermo, Italy
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Jesus RLC, Araujo FA, Alves QL, Dourado KC, Silva DF. Targeting temperature-sensitive transient receptor potential channels in hypertension: far beyond the perception of hot and cold. J Hypertens 2023; 41:1351-1370. [PMID: 37334542 DOI: 10.1097/hjh.0000000000003487] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Transient receptor potential (TRP) channels are nonselective cation channels and participate in various physiological roles. Thus, changes in TRP channel function or expression have been linked to several disorders. Among the many TRP channel subtypes, the TRP ankyrin type 1 (TRPA1), TRP melastatin type 8 (TRPM8), and TRP vanilloid type 1 (TRPV1) channels are temperature-sensitive and recognized as thermo-TRPs, which are expressed in the primary afferent nerve. Thermal stimuli are converted into neuronal activity. Several studies have described the expression of TRPA1, TRPM8, and TRPV1 in the cardiovascular system, where these channels can modulate physiological and pathological conditions, including hypertension. This review provides a complete understanding of the functional role of the opposing thermo-receptors TRPA1/TRPM8/TRPV1 in hypertension and a more comprehensive appreciation of TRPA1/TRPM8/TRPV1-dependent mechanisms involved in hypertension. These channels varied activation and inactivation have revealed a signaling pathway that may lead to innovative future treatment options for hypertension and correlated vascular diseases.
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Affiliation(s)
- Rafael Leonne C Jesus
- Laboratory of Cardiovascular Physiology and Pharmacology, Federal University of Bahia, Salvador
| | - Fênix A Araujo
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation - FIOCRUZ, Bahia, Brazil
| | - Quiara L Alves
- Laboratory of Cardiovascular Physiology and Pharmacology, Federal University of Bahia, Salvador
| | - Keina C Dourado
- Laboratory of Cardiovascular Physiology and Pharmacology, Federal University of Bahia, Salvador
| | - Darizy F Silva
- Laboratory of Cardiovascular Physiology and Pharmacology, Federal University of Bahia, Salvador
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation - FIOCRUZ, Bahia, Brazil
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Liu G, Liu J, Kong X, Xiong WJ, Jiang R. Effect of hypoandrogenism on expression of transient receptor potential vanilloid channels in rat penile corpus cavernosum and erectile function. J Sex Med 2023; 20:1153-1160. [PMID: 37490314 DOI: 10.1093/jsxmed/qdad093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/26/2023]
Abstract
BACKGROUND Hypoandrogenism is a cause of erectile dysfunction (ED). Vascular smooth muscle cell contraction and relaxation are regulated by TRPV1-4 channels. However, the influence of hypoandrogenism on TRPV1-4 and its relationship with erectile function remain unclear. AIM To reveal whether hypoandrogenism affects erectile function by influencing TRPV1-4 expression in the corpus cavernosum of rats. METHODS Male Sprague-Dawley rats (N = 36) aged 8 weeks were assigned to 6 groups at random (n = 6): sham operation, castrated, castrated + testosterone replacement, sham operation + transfection, castrated + transfection, and castrated + empty transfection. Four weeks after castration, 20 μL of lentiviral vector (1 × 108 TU/mL) carrying the TRPV4 gene was injected into the penile cavernous tissue of the transfection groups. One week after transfection, the maximum intracavernous pressure (ICPmax)/mean arterial pressure (MAP) and the content of TRPV1-4, phosphorylated eNOS (p-eNOS)/eNOS, and nitric oxide (NO) in penile cavernous tissue of each group were measured. OUTCOMES Under low androgen conditions, TRPV4 expression in endothelial cells in the rat penile cavernosum was sharply reduced, resulting in a decrease in p-eNOS/eNOS and NO content, which could inhibit erectile function. RESULTS In rat penile cavernous tissue, TRPV1-4 was expressed in the cell membranes of endothelial cells and smooth muscle cells. The ICPmax/MAP and the content of TRPV4, p-eNOS/eNOS, and NO end product nitrite level in rat penile cavernous tissue was markedly reduced in the castrated group as compared with the sham group (P < .05). The ICPmax/MAP and the content of TRPV4, p-eNOS/eNOS, and NO end product nitrite level in rat penile cavernous tissue were markedly improved in the castrated + transfection group vs the castrated group (P < .01). CLINICAL IMPLICATIONS Upregulation of TRPV4 expression in penile cavernosum tissue might be a viable therapeutic for ED caused by hypoandrogenism. STRENGTHS AND LIMITATIONS The specific mechanism of TRPV4 in ED needs to be further verified by androgen receptor or TRPV4 gene knockout experiments. CONCLUSION Hypoandrogenism may cause ED by reducing the expression of TRPV4 in rat penile cavernous tissue. Upregulation of TRPV4 expression in penile cavernous tissue can increase the ratio of p-eNOS/eNOS and NO levels and ameliorate the erectile function of castrated rats.
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Affiliation(s)
- Gang Liu
- Department of Urology, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - Jing Liu
- Department of Urology, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - Xiangjun Kong
- Department of Urology, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - Wen-Ju Xiong
- Department of Urology, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - Rui Jiang
- Department of Urology, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
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Palacios J, Paredes A, Cifuentes F, Catalán MA, García-Villalón AL, Borquez J, Simirgiotis MJ, Jones M, Foster A, Greensmith DJ. A hydroalcoholic extract of Senecio nutans SCh. Bip (Asteraceae); its effects on cardiac function and chemical characterization. JOURNAL OF ETHNOPHARMACOLOGY 2023; 300:115747. [PMID: 36152785 DOI: 10.1016/j.jep.2022.115747] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/07/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
ETHNOPHARMACOLOGY RELEVANCE The plant Senecio nutans SCh. Bip. is used by Andean communities to treat altitude sickness. Recent evidence suggests it may produce vasodilation and negative cardiac inotropy, though the cellular mechanisms have not been elucidated. PURPOSE To determinate the mechanisms action of S. nutans on cardiovascular function in normotensive animals. METHODS The effect of the extract on rat blood pressure was measured with a transducer in the carotid artery and intraventricular pressure by a Langendorff system. The effects on sheep ventricular intracellular calcium handling and contractility were evaluated using photometry. Ultra-high-performance liquid-chromatography with diode array detection coupled with heated electrospray-ionization quadrupole-orbitrap mass spectrometric detection (UHPLC-DAD-ESI-Q-OT-MSn) was used for extract chemical characterization. RESULTS In normotensive rats, S. nutans (10 mg/kg) reduced mean arterial pressure (MAP) by 40% (p < 0.05), causing a dose-dependent coronary artery dilation and decreased left ventricular pressure. In isolated cells, S. nutans extract (1 μg/ml) rapidly reduced the [Ca2+]i transient amplitude and sarcomere shorting by 40 and 49% (p < 0.001), respectively. The amplitude of the caffeine evoked [Ca2+]i transient was reduced by 24% (p < 0.001), indicating reduced sarcoplasmic reticulum (SR) Ca2+ content. Sodium-calcium exchanger (NCX) activity increased by 17% (p < 0.05), while sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) activity was decreased by 21% (p < 0.05). LC-MS results showed the presence of vitamin C, malic acid, and several antioxidant phenolic acids reported for the first time. Dihydroeuparin and 4-hydroxy-3-(3-methylbut-2-enyl) acetophenone were abundant in the extract. CONCLUSION In normotensive animals, S. nutans partially reduces MAP by decreasing heart rate and cardiac contractility. This negative inotropy is accounted for by decreased SERCA activity and increased NCX activity which reduces SR Ca2+ content. These results highlight the plant's potential as a source of novel cardio-active phytopharmaceuticals or nutraceuticals.
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Affiliation(s)
- Javier Palacios
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, 1110939, Chile.
| | - Adrián Paredes
- Departamento de Química, Facultad de Ciencias Básicas, Universidad de Antofagasta, Antofagasta, 1271155, Chile; Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, 1271155, Chile.
| | - Fredi Cifuentes
- Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, 1271155, Chile; Departamento de Biomédico, Facultad Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, 1271155, Chile.
| | - Marcelo A Catalán
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, 5090000, Chile.
| | | | - Jorge Borquez
- Departamento de Química, Facultad de Ciencias Básicas, Universidad de Antofagasta, Antofagasta, 1271155, Chile.
| | - Mario J Simirgiotis
- Center for Interdisciplinary Studies on the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, 5090000, Chile.
| | - Matthew Jones
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom.
| | - Amy Foster
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom.
| | - David J Greensmith
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom.
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Potassium Channels in the Uterine Vasculature: Role in Healthy and Complicated Pregnancies. Int J Mol Sci 2022; 23:ijms23169446. [PMID: 36012712 PMCID: PMC9409294 DOI: 10.3390/ijms23169446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/16/2022] [Accepted: 08/19/2022] [Indexed: 11/28/2022] Open
Abstract
A progressive increase in maternal uterine and placental blood flow must occur during pregnancy to sustain the development of the fetus. Changes in maternal vasculature enable an increased uterine blood flow, placental nutrient and oxygen exchange, and subsequent fetal development. K+ channels are important modulators of vascular function, promoting vasodilation, inducing cell proliferation, and regulating cell signaling. Different types of K+ channels, such as Ca2+-activated, ATP-sensitive, and voltage-gated, have been implicated in the adaptation of maternal vasculature during pregnancy. Conversely, K+ channel dysfunction has been associated with vascular-related complications of pregnancy, including intrauterine growth restriction and pre-eclampsia. In this article, we provide an updated and comprehensive literature review that highlights the relevance of K+ channels as regulators of uterine vascular reactivity and their potential as therapeutic targets.
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Novel Oxime Synthesized from a Natural Product of Senecio nutans SCh. Bip. (Asteraceae) Enhances Vascular Relaxation in Rats by an Endothelium-Independent Mechanism. Molecules 2022; 27:molecules27103333. [PMID: 35630811 PMCID: PMC9146311 DOI: 10.3390/molecules27103333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/17/2022] [Accepted: 05/20/2022] [Indexed: 02/01/2023] Open
Abstract
Senecio nutans Sch. Bip. and its constituents are reported to have antihypertensive effects. We isolated metabolite−1, a natural compound from S. nutans (4-hydroxy-3-(isopenten-2-yl)-acetophenone), and synthesized novel oxime − 1 (4-hydroxy-3-(isopenten-2-yl)-acetophenoxime) to evaluate their effect on vascular reactivity. Compounds were purified (metabolite−1) or synthetized (oxime−1) and characterized using IR and NMR spectroscopy and Heteronuclear Multiple Quantum Coherence (HMQC). Using pharmacological agents such as phenylephrine (PE) and KCl (enhancing contraction), acetylcholine (ACh), L-NAME (nitric oxide (NO) and endothelial function), Bay K8644-induced CaV1.2 channel (calcium channel modulator), and isolated aortic rings in an organ bath setup, the possible mechanisms of vascular action were determined. Pre-incubation of aortic rings with 10−5 M oxime−1 significantly (p < 0.001) decreased the contractile response to 30 mM KCl. EC50 to KCl significantly (p < 0.01) increased in the presence of oxime−1 (37.72 ± 2.10 mM) compared to that obtained under control conditions (22.37 ± 1.40 mM). Oxime−1 significantly reduced (p < 0.001) the contractile response to different concentrations of PE (10−7 to 10−5 M) by a mechanism that decreases Cav1.2-mediated Ca2+ influx from the extracellular space and reduces Ca2+ release from intracellular stores. At a submaximal concentration (10−5 M), oxime−1 caused a significant relaxation in rat aorta even without vascular endothelium or after pre-incubate the tissue with L-NAME. Oxime−1 decreases the contractile response to PE by blunting the release of Ca2+ from intracellular stores and blocking of Ca2+ influx by channels. Metabolite−1 reduces the contractile response to KCl, apparently by reducing the plasma membrane depolarization and Ca2+ influx from the extracellular space. These acetophenone derivates from S. nutans (metabolite−1 and oxime−1) cause vasorelaxation through pathways involving an increase of the endothelial NO generation or a higher bioavailability, further highlighting that structural modification of naturally occurring metabolites can enhance their intended pharmacological functions.
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Đukanović Đ, Gajic Bojic M, Marinkovic S, Trailovic SM, Stojiljković MP, Škrbić R. Vasorelaxant effect of monoterpene carvacrol on isolated human umbilical artery. Can J Physiol Pharmacol 2022; 100:755-762. [PMID: 35507953 DOI: 10.1139/cjpp-2021-0736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carvacrol is the main compound of essential oils extracted primarily from Thymus and Origanum species. Its various biological activities were confirmed: antioxidant, anti-inflammatory, antibacterial, antifungal, anti-tumour, antinematodal and vasorelaxant action. Although vasodilation mediated by carvacrol was previously described, the exact mechanism of its action has not yet been established. Hence, the aim of this study was to investigate carvacrol vasoactivity on human umbilical arteries (HUA) and different pathways involved in its mechanism of action using tissue bath methodology. Carvacrol caused a significant decrease in vascular tension of 5-HT-pre-contracted umbilical arteries, with EC50 of 442.13 ± 33.8 µM (mean ± standard error of the mean - SEM). At 300 µM, carvacrol shifted downward the 5-HT concentration-response curve with statistical significance of p < 0.001 obtained for the four highest concentrations. At concentration of 1 mM, carvacrol completely abolished BaCl2-induced contraction in Ca2+-free Krebs-Ringer bicarbonate solution (p < 0.001). Isopentenyl pyrophosphate, the antagonist of TRPV3 channel, was able to decrease the efficacy of carvacrol (p < 0.001). The vasorelaxant effect of carvacrol seems to involve the blocking of L-type of Ca2+ channels on smooth muscle cells. However, the role of TRPV3 channels in carvacrol-induced vasodilation of HUA cannot be excluded either.
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Affiliation(s)
- Đorđe Đukanović
- University of Banja Luka Faculty of Medicine, 469576, Centre for Biomedical Research, Banja Luka, Bosnia and Herzegovina;
| | - Milica Gajic Bojic
- University of Banja Luka Faculty of Medicine, 469576, Centre for Biomedical Research, Banja Luka, Bosnia and Herzegovina;
| | - Sonja Marinkovic
- University of Banja Luka Faculty of Medicine, 469576, Centre for Biomedical Research, Banja Luka, Bosnia and Herzegovina;
| | - Sasa M Trailovic
- University of Belgrade, 54801, Pharmacology and Toxicology, Bulevar oslobodjenja 18, Beograd, Serbia, 11000;
| | - Miloš P Stojiljković
- University of Banja Luka Faculty of Medicine, 469576, Department of Pharmacology, Toxicology and Clinical Pharmacology, Banja Luka, Bosnia and Herzegovina, 78000;
| | - Ranko Škrbić
- University of Banja Luka Faculty of Medicine, 469576, Banja Luka, Bosnia and Herzegovina, 78000;
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Villegas D, Giard O, Brochu-Gaudreau K, Rousseau É. Activation of TRPV4 channels leads to a consistent tocolytic effect on human myometrial tissues. Eur J Obstet Gynecol Reprod Biol X 2021; 10:100124. [PMID: 33733088 PMCID: PMC7941160 DOI: 10.1016/j.eurox.2021.100124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 02/26/2021] [Indexed: 11/21/2022] Open
Abstract
Specific pharmacological activation of alternative Ca2+ conductance. Activation of TRPV channels, abolishes the rhythmic contractile activity. Tocolysis was consistently induced on human myometrial strips.
Background Human myometrium is a therapeutic target for labor induction and preterm labor. Objective This study aimed to assess the physiological role of alternative calcium conductance on contractions triggered by uterotonic drugs in human myometrium. Membrane conductances, supported by TRPV channels, may provide alternative pathways to control either free intracellular and/or submembrane Ca2+-concentration, which in turn will modulate membrane polarization and contractile responses. Study design Uterine biopsies were obtained from consenting women undergoing elective caesarean delivery at term without labor (N = 22). Isometric tension measurements were performed on uterine smooth muscle strips (n = 132). Amplitude, frequency, and area under the curve (AUC) of phasic contractions, as well as resting tone, were measured under various experimental conditions. Immuno histo- and cyto-chemistry, as well as Western blot analyses, have been performed with specific antibodies against TRPV1, TRPV3, and TRPV4 proteins. TRPV4 agonists; GSK1016790A, 4αPDD, and 5,6-EET were used to assess the role of TRPV4 channels on rhythmic activity triggered by 30–300 nM oxytocin. 5 μM of ruthenium red was used as an efficient blocker of ionic current through TRPV4 channels. Nanomolar concentrations of iberiotoxin (IbTX) were also used to confirm the downstream involvement of BKCa channels in controlling uterine reactivity and contractility. Results The expression of TRPV3 and TRPV4 isoforms has now been demonstrated in human myometrial tissue and cell culture. Nanomolar concentrations of the TRPV4 agonists, (either GSK1016790A or 4αPDD) abolished the rhythmic contractions, resulting in a rapid and consistent tocolytic effect. While 5 μM of ruthenium reversed this tocolytic effect. The addition of IbTX (a BKCa channel blocker) reversed the effects of GSK1016790A. Carvacrol, a TRPV3 agonist, had similar tocolytic effects on rhythmic contractions albeit at higher concentrations. This inhibitory effect was also reversed by ruthenium red. Conclusion Collectively, these data suggest that activation of TRPV4 leads to a Ca2+ entry and subsequent BKCa channel activation (increase in open state probability), which in turn hyperpolarizes the myometrial cell membrane, inactivating L-type Ca2+ channels and efficiently abrogates contractile activity. Consequently, alternative Ca2+ conductance supported by TRPV4 plays a physiological role in the modulation of myometrial reactivity.
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Affiliation(s)
- Daniela Villegas
- Department of Obstetrics and Gynecology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, and Centre de Recherche du CHUS, Sherbrooke, QC, Canada
| | - Olivier Giard
- Department of Obstetrics and Gynecology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, and Centre de Recherche du CHUS, Sherbrooke, QC, Canada
| | - Karine Brochu-Gaudreau
- Department of Obstetrics and Gynecology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, and Centre de Recherche du CHUS, Sherbrooke, QC, Canada
| | - Éric Rousseau
- Department of Obstetrics and Gynecology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, and Centre de Recherche du CHUS, Sherbrooke, QC, Canada
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Saunders SL, Hutchinson DS, Britton FC, Liu L, Markus I, Sandow SL, Murphy TV. Effect of β 1 /β 2 -adrenoceptor blockade on β 3 -adrenoceptor activity in the rat cremaster muscle artery. Br J Pharmacol 2021; 178:1789-1804. [PMID: 33506492 DOI: 10.1111/bph.15398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 01/19/2021] [Accepted: 01/19/2021] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE The physiological role of vascular β3 -adrenoceptors is not fully understood. Recent evidence suggests cardiac β3 -adrenoceptors are functionally effective after down-regulation of β1 /β2 -adrenoceptors. The functional interaction between the β3 -adrenoceptor and other β-adrenoceptor subtypes in rat striated muscle arteries was investigated. EXPERIMENTAL APPROACH Studies were performed in cremaster muscle arteries isolated from male Sprague-Dawley rats. β-adrenoceptor expression was assessed through RT-PCR and immunofluorescence. Functional effects of β3 -adrenoceptor agonists and antagonists and other β-adrenoceptor ligands were measured using pressure myography. KEY RESULTS All three β-adrenoceptor subtypes were present in the endothelium of the cremaster muscle artery. The β3 -adrenoceptor agonists mirabegron and CL 316,243 had no effect on the diameter of pressurized (70 mmHg) cremaster muscle arterioles with myogenic tone, while the β3 -adrenoceptor agonist SR 58611A and the nonselective β-adrenoceptor agonist isoprenaline caused concentration-dependent dilation. In the presence of β1/2 -adrenoceptor antagonists nadolol (10 μM), atenolol (1 μM) and ICI 118,551 (0.1 μM) both mirabegron and CL 316,243 were effective in causing vasodilation and the potency of SR 58611A was enhanced, while responses to isoprenaline were inhibited. The β3 -adrenoceptor antagonist L 748,337 (1 μM) inhibited vasodilation caused by β3 -adrenoceptor agonists (in the presence of β1/2 -adrenoceptor blockade), but L 748,337 had no effect on isoprenaline-induced vasodilation. CONCLUSION AND IMPLICATIONS All three β-adrenoceptor subtypes were present in the endothelium of the rat cremaster muscle artery, but β3 -adrenoceptor mediated vasodilation was only evident after blockade of β1/2 -adrenoceptors. This suggests constitutive β1/2 -adrenoceptor activity inhibits β3 -adrenoceptor function in the endothelium of skeletal muscle resistance arteries.
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Affiliation(s)
- Samantha L Saunders
- Physiology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Dana S Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Fiona C Britton
- Department of Biomedical Sciences, School of Dental Medicine, University of Nevada, Las Vegas, Las Vegas, Nevada, USA
| | - Lu Liu
- Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Irit Markus
- Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Shaun L Sandow
- Physiology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.,Biomedical Science, School of Health and Sports Science, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Timothy V Murphy
- Physiology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
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Munoz-Perez VM, Ortiz MI, Gerardo-Munoz LS, Carino-Cortes R, Salas-Casas A. Tocolytic effect of the monoterpenic phenol isomer, carvacrol, on the pregnant rat uterus. CHINESE J PHYSIOL 2020; 63:204-210. [PMID: 33109786 DOI: 10.4103/cjp.cjp_56_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Despite the wide application of carvacrol (CAR) in different biological and medical areas, there is still insufficient electrophysiological data on the mechanisms of action of CAR, particularly in the pregnant uterine function. The aim of this study was to evaluate the in vitro tocolytic effect of CAR on the contractility of isolated pregnant rat uterus in the presence of a calcium channel antagonist (nifedipine) and a cyclooxygenase inhibitor (indomethacin). The uteri were isolated from pregnant Wistar rats at 16-18 days of pregnancy and suspended in an isolated organ bath chamber containing a Ringer's physiological solution and aerated with 95% O2and 5% CO2. Samples were used in functional tests to evaluate the inhibitory effect of CAR at increasing concentrations on the rhythmic spontaneous, oxytocin-induced phasic, K+-induced tonic, and Ca2+-induced contractions. The differences in inhibitory concentration-50 and Emaxamong the compounds were determined using the one-way ANOVA followed by a post hoc Student-Newman-Keuls or Bonferroni test, in all casesP < 0.05 was considered statistically significant. Nifedipine was used as positive controls where required. CAR caused a significant concentration-dependent inhibition of the uterine contractions induced by the pharmaco- and electro-mechanic stimuli. We showed that the inhibitory effects of CAR depends on the type of muscle contraction stimuli, and that it acts stronger in spontaneous rhythmic activity and in contractions of isolated rat uterus induced by Ca2+. Nifedipine was more potent than CAR and indomethacin on the uterine contractility (P < 0.05), but none of them was more effective than nifedipine. Therefore, the tocolytic effect induced by CAR was associated with the blockade of the calcium channels in the pregnant rat uterus. This property placed CAR as a potentially safe and effective adjuvant agent in cases of preterm labor, an area of pharmacological treatment that requires urgent improvement.
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Affiliation(s)
- Victor Manuel Munoz-Perez
- Department of Pharmacology, Academic Area of Medicine, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
| | - Mario I Ortiz
- Department of Pharmacology, Academic Area of Medicine, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
| | - Lilian S Gerardo-Munoz
- Department of Pharmacology, Academic Area of Medicine, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
| | - Raquel Carino-Cortes
- Department of Pharmacology, Academic Area of Medicine, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
| | - Andrés Salas-Casas
- Department of Geriatrics, Academic Area of Gerontology, Institute of Health Sciences, Autonomous University of the State of Hidalgo, México
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Abstract
Maternal cardiovascular changes during pregnancy include an expansion of plasma volume, increased cardiac output, decreased peripheral resistance, and increased uteroplacental blood flow. These adaptations facilitate the progressive increase in uteroplacental perfusion that is required for normal fetal growth and development, prevent the development of hypertension, and provide a reserve of blood in anticipation of the significant blood loss associated with parturition. Each woman's genotype and phenotype determine her ability to adapt in response to molecular signals that emanate from the fetoplacental unit. Here, we provide an overview of the major hemodynamic and cardiac changes and then consider regional changes in the splanchnic, renal, cerebral, and uterine circulations in terms of endothelial and vascular smooth muscle cell plasticity. Although consideration of gestational disease is beyond the scope of this review, aberrant signaling and/or maternal responsiveness contribute to the etiology of several common gestational diseases such as preeclampsia, intrauterine growth restriction, and gestational diabetes.
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Affiliation(s)
- George Osol
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405, USA;
| | - Nga Ling Ko
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405, USA;
| | - Maurizio Mandalà
- Department of Biology, Ecology and Earth Science, University of Calabria, 87036 Arcavacata di Rende (CS), Italy
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13
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Manoury B, Idres S, Leblais V, Fischmeister R. Ion channels as effectors of cyclic nucleotide pathways: Functional relevance for arterial tone regulation. Pharmacol Ther 2020; 209:107499. [PMID: 32068004 DOI: 10.1016/j.pharmthera.2020.107499] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 02/05/2020] [Indexed: 02/07/2023]
Abstract
Numerous mediators and drugs regulate blood flow or arterial pressure by acting on vascular tone, involving cyclic nucleotide intracellular pathways. These signals lead to regulation of several cellular effectors, including ion channels that tune cell membrane potential, Ca2+ influx and vascular tone. The characterization of these vasocontrictive or vasodilating mechanisms has grown in complexity due to i) the variety of ion channels that are expressed in both vascular endothelial and smooth muscle cells, ii) the heterogeneity of responses among the various vascular beds, and iii) the number of molecular mechanisms involved in cyclic nucleotide signalling in health and disease. This review synthesizes key data from literature that highlight ion channels as physiologically relevant effectors of cyclic nucleotide pathways in the vasculature, including the characterization of the molecular mechanisms involved. In smooth muscle cells, cation influx or chloride efflux through ion channels are associated with vasoconstriction, whereas K+ efflux repolarizes the cell membrane potential and mediates vasodilatation. Both categories of ion currents are under the influence of cAMP and cGMP pathways. Evidence that some ion channels are influenced by CN signalling in endothelial cells will also be presented. Emphasis will also be put on recent data touching a variety of determinants such as phosphodiesterases, EPAC and kinase anchoring, that complicate or even challenge former paradigms.
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Affiliation(s)
- Boris Manoury
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France.
| | - Sarah Idres
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
| | - Véronique Leblais
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
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da Silva RB, Pereira MN, de Araujo RC, Silva WDR, Pereira RAN. A blend of essential oils improved feed efficiency and affected ruminal and systemic variables of dairy cows. Transl Anim Sci 2020; 4:182-193. [PMID: 32704978 PMCID: PMC6994060 DOI: 10.1093/tas/txz183] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 12/16/2019] [Indexed: 11/21/2022] Open
Abstract
This experiment evaluated the effect of a blend of essential oils (BEO) on intake, lactation performance, diet digestibility, ruminal fermentation profile, eating behavior, body thermoregulation, blood acid-base balance, and milk fatty acid profile of lactating cows. Twenty-eight Holstein cows were individually fed a standard diet for 14 d and treatments control or BEO (a microencapsulated blend of pepper extract containing capsaicin and pure forms of carvacrol, cinnamaldehyde, and eugenol; 150 mg/kg of diet dry matter) for 56 d. Significance was declared at P ≤ 0.05 and trends at 0.05 < P ≤ 0.10. Dry matter intake (DMI) was reduced (19.5 vs. 20.1 kg/d) and milk yield was increased (30.1 vs. 30.8 kg/d) by BEO, inducing improved milk to DMI ratio (1.53 vs. 1.62). Milk fat concentration tended to be increased by BEO, but total solids yield did not differ. There was a trend for increased total tract non-neutral detergent fiber organic matter digestibility with BEO. The molar proportion of acetate in ruminal fluid was reduced (51.4 vs. 57.8%) and that of propionate was increased (26.1 vs. 31.3%) by BEO. Ruminal microbial yield and total protozoa count in ruminal fluid did not differ. Cows fed BEO ingested a greater proportion of the daily intake in the morning (30.6 vs. 36.6%) and tended to ingest a lower proportion at night, tended to have longer meals, and had fewer meals per day (11.9 vs. 13.7) and larger meal size (1.5 vs. 1.7 kg of dry matter per meal). Blood urea-N and glucose concentrations did not differ. The BEO increased jugular blood oxygenation. The sweating rate on a hot and dry day was increased (160 vs. 221 g/m2/h) by BEO. The mean rectal and skin temperatures and respiration rate did not differ, but the proportion of rectal temperature measurements ≥39.2 °C was reduced by BEO at 1400 h (17.8 vs. 28.5%) and 2000 h (23.2 vs. 34.8%). The BEO increased the secretion (g/d) of 18:2 trans-10, cis-12 and the concentration of 18:0 iso fatty acids in milk fat. When one sample of milk from BEO cows was offered with two samples of milk from control, 59% of regular consumers of milk (n = 63) identified the odd sample correctly. The gain in feed efficiency induced by BEO was associated with reduced acetate-to-propionate ratio in ruminal fluid, altered eating behavior, lower frequency of high rectal temperature, and increased blood oxygenation. Essential oils had positive effects on ruminal fermentation and systemic variables of dairy cows.
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Affiliation(s)
- Rayana Brito da Silva
- Departamento de Zootecnia, Universidade Federal de Lavras, Lavras, MG, Brazil
- Better Nature Research Center, Ijaci, MG, Brazil
| | - Marcos Neves Pereira
- Departamento de Zootecnia, Universidade Federal de Lavras, Lavras, MG, Brazil
- Better Nature Research Center, Ijaci, MG, Brazil
| | | | | | - Renata Apocalypse Nogueira Pereira
- Better Nature Research Center, Ijaci, MG, Brazil
- Empresa de Pesquisa Agropecuária de Minas Gerais, Unidade Regional Sul de Minas, Lavras, MG, Brazil
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Thakore P, Earley S. Transient Receptor Potential Channels and Endothelial Cell Calcium Signaling. Compr Physiol 2019; 9:1249-1277. [PMID: 31187891 DOI: 10.1002/cphy.c180034] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The vascular endothelium is a broadly distributed and highly specialized organ. The endothelium has a number of functions including the control of blood vessels diameter through the production and release of potent vasoactive substances or direct electrical communication with underlying smooth muscle cells, regulates the permeability of the vascular barrier, stimulates the formation of new blood vessels, and influences inflammatory and thrombotic processes. Endothelial cells that make up the endothelium express a variety of cell-surface receptors and ion channels on the plasma membrane that are capable of detecting circulating hormones, neurotransmitters, oxygen tension, and shear stress across the vascular wall. Changes in these stimuli activate signaling cascades that initiate an appropriate physiological response. Increases in the global intracellular Ca2+ concentration and localized Ca2+ signals that occur within specialized subcellular microdomains are fundamentally important components of many signaling pathways in the endothelium. The transient receptor potential (TRP) channels are a superfamily of cation-permeable ion channels that act as a primary means of increasing cytosolic Ca2+ in endothelial cells. Consequently, TRP channels are vitally important for the major functions of the endothelium. In this review, we provide an in-depth discussion of Ca2+ -permeable TRP channels in the endothelium and their role in vascular regulation. © 2019 American Physiological Society. Compr Physiol 9:1249-1277, 2019.
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Affiliation(s)
- Pratish Thakore
- Department of Pharmacology, Center for Cardiovascular Research, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Scott Earley
- Department of Pharmacology, Center for Cardiovascular Research, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
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16
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Agonist-evoked endothelial Ca 2+ signalling microdomains. Curr Opin Pharmacol 2019; 45:8-15. [PMID: 30986569 DOI: 10.1016/j.coph.2019.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/03/2019] [Accepted: 03/15/2019] [Indexed: 01/14/2023]
Abstract
Localized, oscillating Ca2+ signals have been identified in discrete microdomains of vascular endothelial cells. At myoendothelial contacts (between endothelial and smooth muscle cells), both endothelial Ca2+ pulsars (IP3-mediated release of intracellular Ca2+) and Ca2+ sparklets (extracellular Ca2+ entry via TRP channels) contribute to endothelium-dependent hyperpolarization of smooth muscle, vasodilation, and feedback control of vasoconstriction. Ca2+ sparklets occurring at close-contact domains between endothelial cells are possibly involved in conducted hyperpolarization and spreading vasodilation in arterial networks. This review summarizes these Ca2+ signalling phenomena, examines the proposed mechanisms leading to their generation by G-protein-coupled receptor agonists, and explores the proposed physiological roles of these localized and specialized Ca2+ signals.
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17
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Fromy B, Josset-Lamaugarny A, Aimond G, Pagnon-Minot A, Marics I, Tattersall GJ, Moqrich A, Sigaudo-Roussel D. Disruption of TRPV3 Impairs Heat-Evoked Vasodilation and Thermoregulation: A Critical Role of CGRP. J Invest Dermatol 2018; 138:688-696. [DOI: 10.1016/j.jid.2017.10.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 09/08/2017] [Accepted: 10/08/2017] [Indexed: 12/24/2022]
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18
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Alonso-Carbajo L, Kecskes M, Jacobs G, Pironet A, Syam N, Talavera K, Vennekens R. Muscling in on TRP channels in vascular smooth muscle cells and cardiomyocytes. Cell Calcium 2017; 66:48-61. [PMID: 28807149 DOI: 10.1016/j.ceca.2017.06.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 02/07/2023]
Abstract
The human TRP protein family comprises a family of 27 cation channels with diverse permeation and gating properties. The common theme is that they are very important regulators of intracellular Ca2+ signaling in diverse cell types, either by providing a Ca2+ influx pathway, or by depolarising the membrane potential, which on one hand triggers the activation of voltage-gated Ca2+ channels, and on the other limits the driving force for Ca2+ entry. Here we focus on the role of these TRP channels in vascular smooth muscle and cardiac striated muscle. We give an overview of highlights from the recent literature, and highlight the important and diverse roles of TRP channels in the pathophysiology of the cardiovascular system. The discovery of the superfamily of Transient Receptor Potential (TRP) channels has significantly enhanced our knowledge of multiple signal transduction mechanisms in cardiac muscle and vascular smooth muscle cells (VSMC). In recent years, multiple studies have provided evidence for the involvement of these channels, not only in the regulation of contraction, but also in cell proliferation and remodeling in pathological conditions. The mammalian family of TRP cation channels is composed by 28 genes which can be divided into 6 subfamilies groups based on sequence similarity: TRPC (Canonical), TRPM (Melastatin), TRPML (Mucolipins), TRPV (Vanilloid), TRPP (Policystin) and TRPA (Ankyrin-rich protein). Functional TRP channels are believed to form four-unit complexes in the plasma, each of them expressed with six transmembrane domain and intracellular N and C termini. Here we review the current knowledge on the expression of TRP channels in both muscle types, and discuss their functional properties and role in physiological and pathophysiological processes.
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Affiliation(s)
- Lucía Alonso-Carbajo
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Miklos Kecskes
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Griet Jacobs
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Andy Pironet
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Ninda Syam
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Karel Talavera
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium.
| | - Rudi Vennekens
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium.
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19
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20
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Transient receptor potential canonical type 3 channels: Interactions, role and relevance - A vascular focus. Pharmacol Ther 2017; 174:79-96. [DOI: 10.1016/j.pharmthera.2017.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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21
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Mechanisms and time course of menthol-induced cutaneous vasodilation. Microvasc Res 2016; 110:43-47. [PMID: 27899298 DOI: 10.1016/j.mvr.2016.11.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/20/2016] [Accepted: 11/22/2016] [Indexed: 11/23/2022]
Abstract
Menthol is a vasoactive compound that is widely used in topical analgesic agents. Menthol induces cutaneous vasodilation, however the underlying mechanisms are unknown. Determining the rates of appearance and clearance of menthol in the skin is important for optimizing topical treatment formulation and dosing. The purpose of this study was to determine the mechanisms contributing to menthol-mediated cutaneous vasodilation and to establish a time course for menthol appearance/clearance in the skin. Ten young (23±1years, 5 males 5 females) subjects participated in two protocols. In study 1, four intradermal microdialysis fibers were perfused with increasing doses of menthol (0.1-500mM) and inhibitors for nitric oxide (NO), endothelium derived hyperpolarizing factors (EDHFs), and sensory nerves. Skin blood flow was measured with laser Doppler flowmetry and normalized to %CVCmax. In study 2, two intradermal microdialysis fibers were perfused with lactated Ringer's solution. 0.017mL·cm-2 of a 4% menthol gel was placed over each fiber. 5μL samples of dialysate from the microdialysis fibers were collected every 30min and analyzed for the presence of menthol with high performance gas chromatography/mass spectrometry. Skin blood flow (laser speckle contrast imaging) and subjective ratings of menthol sensation were simultaneously obtained with dialysate samples. In study 1, menthol induced cutaneous vasodilation at all doses ≥100mM (all p<0.05). However, inhibition of either NO, EDHFs, or sensory nerves fully inhibited menthol-mediated vasodilation (all p>0.05). In study 2, significant menthol was detected in dialysate 30min post menthol application (0.89ng, p=0.0002). Relative to baseline, cutaneous vasodilation was elevated from minutes 15-45 and ratings of menthol sensation were elevated from minute 5-60 post menthol application (all p<0.05). Menthol induces cutaneous vasodilation in the skin through multiple vasodilator pathways, including NO, EDHF, and sensory nerves. Topical menthol is detectable in the skin within 30min and is cleared by 60min. Skin blood flow and perceptual measures follow a similar time course as menthol appearance/clearance.
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