1
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Manning D, Rivera EJ, Santana LF. The life cycle of a capillary: Mechanisms of angiogenesis and rarefaction in microvascular physiology and pathologies. Vascul Pharmacol 2024; 156:107393. [PMID: 38857638 DOI: 10.1016/j.vph.2024.107393] [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: 04/25/2024] [Revised: 06/02/2024] [Accepted: 06/07/2024] [Indexed: 06/12/2024]
Abstract
Capillaries are the smallest blood vessels (<10 μm in diameter) in the body and their walls are lined by endothelial cells. These microvessels play a crucial role in nutrient and gas exchange between blood and tissues. Capillary endothelial cells also produce vasoactive molecules and initiate the electrical signals that underlie functional hyperemia and neurovascular coupling. Accordingly, capillary function and density are critical for all cell types to match blood flow to cellular activity. This begins with the process of angiogenesis, when new capillary blood vessels emerge from pre-existing vessels, and ends with rarefaction, the loss of these microvascular structures. This review explores the mechanisms behind these processes, emphasizing their roles in various microvascular diseases and their impact on surrounding cells in health and disease. We discuss recent work on the mechanisms controlling endothelial cell proliferation, migration, and tube formation that underlie angiogenesis under physiological and pathological conditions. The mechanisms underlying functional and anatomical rarefaction and the role of pericytes in this process are also discussed. Based on this work, a model is proposed in which the balance of angiogenic and rarefaction signaling pathways in a particular tissue match microvascular density to the metabolic demands of the surrounding cells. This negative feedback loop becomes disrupted during microvascular rarefaction: angiogenic mechanisms are blunted, reactive oxygen species accumulate, capillary function declines and eventually, capillaries disappear. This, we propose, forms the foundation of the reciprocal relationship between vascular density, blood flow, and metabolic needs and functionality of nearby cells.
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Affiliation(s)
- Declan Manning
- Department of Physiology & Membrane Biology, School of Medicine, University of California, Davis, United States of America.
| | - Ernesto J Rivera
- Department of Physiology & Membrane Biology, School of Medicine, University of California, Davis, United States of America
| | - L Fernando Santana
- Department of Physiology & Membrane Biology, School of Medicine, University of California, Davis, United States of America
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Behringer EJ. Impact of aging on vascular ion channels: perspectives and knowledge gaps across major organ systems. Am J Physiol Heart Circ Physiol 2023; 325:H1012-H1038. [PMID: 37624095 PMCID: PMC10908410 DOI: 10.1152/ajpheart.00288.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/21/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023]
Abstract
Individuals aged ≥65 yr will comprise ∼20% of the global population by 2030. Cardiovascular disease remains the leading cause of death in the world with age-related endothelial "dysfunction" as a key risk factor. As an organ in and of itself, vascular endothelium courses throughout the mammalian body to coordinate blood flow to all other organs and tissues (e.g., brain, heart, lung, skeletal muscle, gut, kidney, skin) in accord with metabolic demand. In turn, emerging evidence demonstrates that vascular aging and its comorbidities (e.g., neurodegeneration, diabetes, hypertension, kidney disease, heart failure, and cancer) are "channelopathies" in large part. With an emphasis on distinct functional traits and common arrangements across major organs systems, the present literature review encompasses regulation of vascular ion channels that underlie blood flow control throughout the body. The regulation of myoendothelial coupling and local versus conducted signaling are discussed with new perspectives for aging and the development of chronic diseases. Although equipped with an awareness of knowledge gaps in the vascular aging field, a section has been included to encompass general feasibility, role of biological sex, and additional conceptual and experimental considerations (e.g., cell regression and proliferation, gene profile analyses). The ultimate goal is for the reader to see and understand major points of deterioration in vascular function while gaining the ability to think of potential mechanistic and therapeutic strategies to sustain organ perfusion and whole body health with aging.
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Affiliation(s)
- Erik J Behringer
- Basic Sciences, Loma Linda University, Loma Linda, California, United States
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3
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Daneva Z, Chen Y, Ta HQ, Manchikalapudi V, Bazaz A, Laubach VE, Sonkusare SK. Endothelial IK and SK channel activation decreases pulmonary arterial pressure and vascular remodeling in pulmonary hypertension. Pulm Circ 2023; 13:e12186. [PMID: 36686408 PMCID: PMC9841469 DOI: 10.1002/pul2.12186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/20/2022] [Accepted: 12/29/2022] [Indexed: 01/09/2023] Open
Abstract
Endothelial cells (ECs) from small pulmonary arteries (PAs) release nitric oxide (NO) and prostacyclin, which lower pulmonary arterial pressure (PAP). In pulmonary hypertension (PH), the levels of endothelium-derived NO and prostacyclin are reduced, contributing to elevated PAP. Small-and intermediate-conductance Ca2+-activated K+ channels (IK and SK)-additional crucial endothelial mediators of vasodilation-are also present in small PAs, but their function has not been investigated in PH. We hypothesized that endothelial IK and SK channels can be targeted to lower PAP in PH. Whole-cell patch-clamp experiments showed functional IK and SK channels in ECs, but not smooth muscle cells, from small PAs. Using a SU5416 plus chronic hypoxia (Su + CH) mouse model of PH, we found that currents through EC IK and SK channels were unchanged compared with those from normal mice. Moreover, IK/SK channel-mediated dilation of small PAs was preserved in Su + CH mice. Consistent with previous reports, endothelial NO levels and NO-mediated dilation were reduced in small PAs from Su + CH mice. Notably, acute treatment with IK/SK channel activators decreased PAP in Su + CH mice but not in normal mice. Further, chronic activation of IK/SK channels decreased PA remodeling and right ventricular hypertrophy, which are pathological hallmarks of PH, in Su + CH mice. Collectively, our data provide the first evidence that, unlike endothelial NO release, IK/SK channel activity is not altered in PH. Our results also demonstrate proof of principle that IK/SK channel activation can be used as a strategy for lowering PAP in PH.
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Affiliation(s)
- Zdravka Daneva
- Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Yen‐Lin Chen
- Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Huy Q. Ta
- Department of SurgeryUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Vamsi Manchikalapudi
- Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Abhishek Bazaz
- Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Victor E. Laubach
- Department of SurgeryUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Swapnil K. Sonkusare
- Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA,Department of Molecular Physiology and Biological PhysicsUniversity of VirginiaCharlottesvilleVirginiaUSA
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4
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Metabolic regulation and dysregulation of endothelial small conductance calcium activated potassium channels. Eur J Cell Biol 2022; 101:151208. [DOI: 10.1016/j.ejcb.2022.151208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/13/2022] Open
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5
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Kloza M, Baranowska-Kuczko M, Toczek M, Kusaczuk M, Sadowska O, Kasacka I, Kozłowska H. Modulation of Cardiovascular Function in Primary Hypertension in Rat by SKA-31, an Activator of KCa2.x and KCa3.1 Channels. Int J Mol Sci 2019; 20:ijms20174118. [PMID: 31450834 PMCID: PMC6747311 DOI: 10.3390/ijms20174118] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/17/2019] [Accepted: 08/21/2019] [Indexed: 12/11/2022] Open
Abstract
The aim of this study was to investigate the hemodynamic effects of SKA-31, an activator of the small (KCa2.x) and intermediate (KCa3.1) conductance calcium-activated potassium channels, and to evaluate its influence on endothelium-derived hyperpolarization (EDH)-KCa2.3/KCa3.1 type relaxation in isolated endothelium-intact small mesenteric arteries (sMAs) from spontaneously hypertensive rats (SHRs). Functional in vivo and in vitro experiments were performed on SHRs or their normotensive controls, Wistar-Kyoto rats (WKY). SKA-31 (1, 3 and 10 mg/kg) caused a brief decrease in blood pressure and bradycardia in both SHR and WKY rats. In phenylephrine-pre-constricted sMAs of SHRs, SKA-31 (0.01–10 µM)-mediated relaxation was reduced and SKA-31 potentiated acetylcholine-evoked endothelium-dependent relaxation. Endothelium denudation and inhibition of nitric oxide synthase (eNOS) and cyclooxygenase (COX) by the respective inhibitors l-NAME or indomethacin, attenuated SKA-31-mediated vasorelaxation. The inhibition of KCa3.1, KCa2.3, KIR and Na+/K+-ATPase by TRAM-34, UCL1684, Ba2+ and ouabain, respectively, reduced the potency and efficacy of the EDH-response evoked by SKA-31. The mRNA expression of eNOS, prostacyclin synthase, KCa2.3, KCa3.1 and KIR were decreased, while Na+/K+-ATPase expression was increased. Collectively, SKA-31 promoted hypotension and vasodilatation, potentiated agonist-stimulated vasodilation, and maintained KCa2.3/KCa3.1-EDH-response in sMAs of SHR with downstream signaling that involved KIR and Na+/K+-ATPase channels. In view of the importance of the dysfunction of endothelium-mediated vasodilatation in the mechanism of hypertension, application of activators of KCa2.3/KCa3.1 channels such as SKA-31 seem to be a promising avenue in pharmacotherapy of hypertension.
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Affiliation(s)
- Monika Kloza
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland
| | - Marta Baranowska-Kuczko
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland
- Department of Clinical Pharmacy, Medical University of Białystok, 15-222 Białystok, Poland
| | - Marek Toczek
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland
| | - Magdalena Kusaczuk
- Department of Pharmaceutical Biochemistry, Medical University of Białystok, 15-222 Białystok, Poland
| | - Olga Sadowska
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland
| | - Irena Kasacka
- Department of Histology and Cytophysiology, Medical University of Białystok, 15-222 Białystok, Poland
| | - Hanna Kozłowska
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, 15-222 Białystok, Poland.
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Oxidative stress induced by palmitic acid modulates K Ca2.3 channels in vascular endothelium. Exp Cell Res 2019; 383:111552. [PMID: 31415760 DOI: 10.1016/j.yexcr.2019.111552] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 07/27/2019] [Accepted: 08/10/2019] [Indexed: 02/08/2023]
Abstract
Elevated plasma free fatty acids level has been implicated in the development of insulin resistance, inflammation, and endothelial dysfunction in diabetic and nondiabetic individuals. However, the underlying mechanisms still remain to be defined. Herein, we investigated the effect of palmitic acid (PA), the most abundant saturated fatty acid in the human body, on small-conductance Ca2+-activated potassium channels (KCa2.3)-mediated relaxation in rodent resistance arteries and the underlying molecular mechanism. The effect of PA on KCa2.3 in endothelium was evaluated using real-time PCR, Western blotting, whole-cell patch voltage-clamp, wire and pressure myograph system, and reactive oxygen species (ROS) were measured by using dihydroethidium and 2', 7'-dichlorofluorescein diacetate. KCa2.3-mediated vasodilatation responses to acetylcholine and NS309 (agonist of KCa2.3 and KCa3.1) were impaired by incubation of normal mesenteric arteries with 100 μM PA for 24 h. In cultured human umbilical vein endothelial cells (HUVECs), PA decreased KCa2.3 current and expression at mRNA and protein levels. Incubation with the NADPH oxidase (Nox) inhibitor dibenziodolium (DPI) partly inhibited the PA-induced ROS production and restored KCa2.3 expression. Inhibition of either p38-MAPK or NF-κB using specific inhibitors (SB203580, SB202190 or Bay11-7082, pyrrolidinedithiocarbamate) attenuated PA-induced downregulation of KCa2.3 and inhibition of p38-MAPK also attenuated PA-induced phosphorylation of NF-κB p65. Furthermore, DPI reversed the increment of phospho-p38-MAPK by PA. These results demonstrated that PA downregulated KCa2.3 expressions via Nox/ROS/p38-MAPK/NF-κB signaling leading to endothelial vasodilatory dysfunction.
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Khaddaj Mallat R, Mathew John C, Mishra RC, Kendrick DJ, Braun AP. Pharmacological Targeting of KCa Channels to Improve Endothelial Function in the Spontaneously Hypertensive Rat. Int J Mol Sci 2019; 20:ijms20143481. [PMID: 31315169 PMCID: PMC6678254 DOI: 10.3390/ijms20143481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 07/05/2019] [Accepted: 07/12/2019] [Indexed: 01/01/2023] Open
Abstract
Systemic hypertension is a major risk factor for the development of cardiovascular disease and is often associated with endothelial dysfunction. KCa2.3 and KCa3.1 channels are expressed in the vascular endothelium and contribute to stimulus-evoked vasodilation. We hypothesized that acute treatment with SKA-31, a selective activator of KCa2.x and KCa3.1 channels, would improve endothelium-dependent vasodilation and transiently lower mean arterial pressure (MAP) in male, spontaneously hypertensive rats (SHRs). Isolated vascular preparations exhibited impaired vasodilation in response to bradykinin (i.e., endothelial dysfunction) compared with Wistar controls, which was associated with decreased bradykinin receptor expression in mesenteric arteries. In contrast, similar levels of endothelial KCa channel expression were observed, and SKA-31 evoked vasodilation was comparable in vascular preparations from both strains. Addition of a low concentration of SKA-31 (i.e., 0.2–0.3 μM) failed to augment bradykinin-induced vasodilation in arteries from SHRs. However, responses to acetylcholine were enhanced. Surprisingly, acute bolus administration of SKA-31 in vivo (30 mg/kg, i.p. injection) modestly elevated MAP compared with vehicle injection. In summary, pharmacological targeting of endothelial KCa channels in SHRs did not readily reverse endothelial dysfunction in situ, or lower MAP in vivo. SHRs thus appear to be less responsive to endothelial KCa channel activators, which may be related to their vascular pathology.
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Affiliation(s)
- Rayan Khaddaj Mallat
- Department of Physiology and Pharmacology and Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Cini Mathew John
- Department of Physiology and Pharmacology and Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Ramesh C Mishra
- Department of Physiology and Pharmacology and Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Dylan J Kendrick
- Department of Physiology and Pharmacology and Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Andrew P Braun
- Department of Physiology and Pharmacology and Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
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8
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Behringer EJ, Hakim MA. Functional Interaction among K Ca and TRP Channels for Cardiovascular Physiology: Modern Perspectives on Aging and Chronic Disease. Int J Mol Sci 2019; 20:ijms20061380. [PMID: 30893836 PMCID: PMC6471369 DOI: 10.3390/ijms20061380] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/07/2019] [Accepted: 03/15/2019] [Indexed: 12/16/2022] Open
Abstract
Effective delivery of oxygen and essential nutrients to vital organs and tissues throughout the body requires adequate blood flow supplied through resistance vessels. The intimate relationship between intracellular calcium ([Ca2+]i) and regulation of membrane potential (Vm) is indispensable for maintaining blood flow regulation. In particular, Ca2+-activated K+ (KCa) channels were ascertained as transducers of elevated [Ca2+]i signals into hyperpolarization of Vm as a pathway for decreasing vascular resistance, thereby enhancing blood flow. Recent evidence also supports the reverse role for KCa channels, in which they facilitate Ca2+ influx into the cell interior through open non-selective cation (e.g., transient receptor potential; TRP) channels in accord with robust electrical (hyperpolarization) and concentration (~20,000-fold) transmembrane gradients for Ca2+. Such an arrangement supports a feed-forward activation of Vm hyperpolarization while potentially boosting production of nitric oxide. Furthermore, in vascular types expressing TRP channels but deficient in functional KCa channels (e.g., collecting lymphatic endothelium), there are profound alterations such as downstream depolarizing ionic fluxes and the absence of dynamic hyperpolarizing events. Altogether, this review is a refined set of evidence-based perspectives focused on the role of the endothelial KCa and TRP channels throughout multiple experimental animal models and vascular types. We discuss the diverse interactions among KCa and TRP channels to integrate Ca2+, oxidative, and electrical signaling in the context of cardiovascular physiology and pathology. Building from a foundation of cellular biophysical data throughout a wide and diverse compilation of significant discoveries, a translational narrative is provided for readers toward the treatment and prevention of chronic, age-related cardiovascular disease.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, 11041 Campus Street, Risley Hall, Loma Linda University, Loma Linda, CA 92350, USA.
| | - Md A Hakim
- Department of Basic Sciences, 11041 Campus Street, Risley Hall, Loma Linda University, Loma Linda, CA 92350, USA.
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Olchanheski LR, Sordi R, Oliveira JG, Alves GF, Mendes RT, Santos FA, Fernandes D. The role of potassium channels in the endothelial dysfunction induced by periodontitis. J Appl Oral Sci 2018; 26:e20180048. [PMID: 30304126 PMCID: PMC6172022 DOI: 10.1590/1678-7757-2018-0048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/18/2018] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE Periodontitis is associated with endothelial dysfunction, which is clinically characterized by a reduction in endothelium-dependent relaxation. However, we have previously shown that impairment in endothelium-dependent relaxation is transient. Therefore, we evaluated which mediators are involved in endothelium-dependent relaxation recovery. MATERIAL AND METHODS Rats were subjected to ligature-induced experimental periodontitis. Twenty-one days after the procedure, the animals were prepared for blood pressure recording, and the responses to acetylcholine or sodium nitroprusside were obtained before and 30 minutes after injection of a nitric oxide synthase inhibitor (L-NAME), cyclooxygenase inhibitor (Indomethacin, SC-550 and NS- 398), or calcium-dependent potassium channel blockers (apamin plus TRAM- 34). The maxilla and mandible were removed for bone loss analysis. Blood and gingivae were obtained for C-reactive protein (CRP) and myeloperoxidase (MPO) measurement, respectively. RESULTS Experimental periodontitis induces bone loss and an increase in the gingival MPO and plasmatic CRP. Periodontitis also reduced endothelium-dependent vasodilation, a hallmark of endothelial dysfunction, 14 days after the procedure. However, the response was restored at day 21. We found that endothelium-dependent vasodilation at day 21 in ligature animals was mediated, at least in part, by the activation of endothelial calcium-activated potassium channels. CONCLUSIONS Periodontitis induces impairment in endothelial-dependent relaxation; this impairment recovers, even in the presence of periodontitis. The recovery is mediated by the activation of endothelial calcium-activated potassium channels in ligature animals. Although important for maintenance of vascular homeostasis, this effect could mask the lack of NO, which has other beneficial properties.
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Affiliation(s)
- Luiz Renato Olchanheski
- Universidade Estadual de Ponta Grossa, Departamento de Ciências Farmacêuticas, Ponta Grossa, Paraná, Brasil
| | - Regina Sordi
- Universidade Estadual de Ponta Grossa, Departamento de Ciências Farmacêuticas, Ponta Grossa, Paraná, Brasil.,Universidade Estadual de Ponta Grossa, Departamento de Biologia Molecular e Genética, Ponta Grossa, Paraná, Brasil
| | - Junior Garcia Oliveira
- Universidade Estadual de Ponta Grossa, Departamento de Ciências Farmacêuticas, Ponta Grossa, Paraná, Brasil
| | - Gustavo Ferreira Alves
- Universidade Federal de Santa Catarina, Departamento de Farmacologia, Florianópolis, Santa Catarina, Brasil
| | - Reila Taina Mendes
- Universidade Estadual de Ponta Grossa, Departamento de Odontologia, Ponta Grossa, Paraná, Brasil
| | - Fábio André Santos
- Universidade Estadual de Ponta Grossa, Departamento de Odontologia, Ponta Grossa, Paraná, Brasil
| | - Daniel Fernandes
- Universidade Federal de Santa Catarina, Departamento de Farmacologia, Florianópolis, Santa Catarina, Brasil
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Martinez-Quinones P, McCarthy CG, Watts SW, Klee NS, Komic A, Calmasini FB, Priviero F, Warner A, Chenghao Y, Wenceslau CF. Hypertension Induced Morphological and Physiological Changes in Cells of the Arterial Wall. Am J Hypertens 2018; 31:1067-1078. [PMID: 29788246 DOI: 10.1093/ajh/hpy083] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/14/2018] [Indexed: 12/17/2022] Open
Abstract
Morphological and physiological changes in the vasculature have been described in the evolution and maintenance of hypertension. Hypertension-induced vascular dysfunction may present itself as a contributing, or consequential factor, to vascular remodeling caused by chronically elevated systemic arterial blood pressure. Changes in all vessel layers, from the endothelium to the perivascular adipose tissue (PVAT), have been described. This mini-review focuses on the current knowledge of the structure and function of the vessel layers, specifically muscular arteries: intima, media, adventitia, PVAT, and the cell types harbored within each vessel layer. The contributions of each cell type to vessel homeostasis and pathophysiological development of hypertension will be highlighted.
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Affiliation(s)
- Patricia Martinez-Quinones
- Department of Surgery, Medical College of Georgia at Augusta University, Augusta, Georgia
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Cameron G McCarthy
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Stephanie W Watts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Nicole S Klee
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Amel Komic
- Department of Surgery, Medical College of Georgia at Augusta University, Augusta, Georgia
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Fabiano B Calmasini
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Fernanda Priviero
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Alexander Warner
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Yu Chenghao
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Camilla F Wenceslau
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
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11
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Ando M, Matsumoto T, Kobayashi S, Iguchi M, Taguchi K, Kobayashi T. Differential participation of calcium-activated potassium channel in endothelium-dependent hyperpolarization-type relaxation in superior mesenteric arteries of spontaneously hypertensive rats. Can J Physiol Pharmacol 2018; 96:839-844. [PMID: 29558628 DOI: 10.1139/cjpp-2017-0557] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to determine the relationship of KCa channels to endothelium-dependent hyperpolarizing factor (EDHF)-mediated relaxation induced by acetylcholine (ACh) in the superior mesenteric arteries of 7-month-old spontaneously hypertensive rats (SHR). Upon inhibition of nitric oxide synthase and cyclooxygenase, ACh-induced EDHF-mediated relaxation was found to be weaker in SHR than in age-matched Wistar Kyoto rats (WKY). These relaxations in both group were attenuated by combined treatment with small-conductance and intermediate-conductance Ca2+-activated K+ channels (SKCa and IKCa) inhibitors, with the exception of relaxation resistant to inhibition of these channels in SHR (vs. WKY). Treatment with large-conductance Ca2+-activated K+ channels (BKCa) inhibitor specifically attenuated relaxation in SHR, but not in WKY. Protein expression of IKCa and SKCa in the arteries did not differ between the 2 groups, whereas ratio of sloβ1 subunit to α subunit of BKCa was increased in SHR (vs. WKY). These results suggest that EDHF-mediated relaxations in superior mesenteric arteries are impaired in SHR, and utilize components of BKCa in addition to SKCa/IKCa channel activities, that the increased participation of BKCa may be attributable to alterations in α and sloβ1 subunit ratio, and that components unrelated to KCa activity may also contribute to the difference between SHR and WKY arteries.
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Affiliation(s)
- Makoto Ando
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan.,Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan.,Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Shota Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan.,Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Maika Iguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan.,Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Kumiko Taguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan.,Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan.,Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
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12
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Behringer EJ. Calcium and electrical signaling in arterial endothelial tubes: New insights into cellular physiology and cardiovascular function. Microcirculation 2018; 24. [PMID: 27801542 DOI: 10.1111/micc.12328] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/25/2016] [Indexed: 12/23/2022]
Abstract
The integral role of the endothelium during the coordination of blood flow throughout vascular resistance networks has been recognized for several decades now. Early examination of the distinct anatomy and physiology of the endothelium as a signaling conduit along the vascular wall has prompted development and application of an intact endothelial "tube" study model isolated from rodent skeletal muscle resistance arteries. Vasodilatory signals such as increased endothelial cell (EC) Ca2+ ([Ca2+ ]i ) and hyperpolarization take place in single ECs while shared between electrically coupled ECs through gap junctions up to distances of millimeters (≥2 mm). The small- and intermediate-conductance Ca2+ activated K+ (SKCa /IKCa or KCa 2.3/KCa 3.1) channels function at the interface of Ca2+ signaling and hyperpolarization; a bidirectional relationship whereby increases in [Ca2+ ]i activate SKCa /IKCa channels to produce hyperpolarization and vice versa. Further, the spatial domain of hyperpolarization among electrically coupled ECs can be finely tuned via incremental modulation of SKCa /IKCa channels to balance the strength of local and conducted electrical signals underlying vasomotor activity. Multifunctional properties of the voltage-insensitive SKCa /IKCa channels of resistance artery endothelium may be employed for therapy during the aging process and development of vascular disease.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, Loma Linda University, Loma Linda, CA, USA
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13
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Wynne BM, Labazi H, Lima VV, Carneiro FS, Webb RC, Tostes RC, Giachini FR. Mesenteric arteries from stroke-prone spontaneously hypertensive rats exhibit an increase in nitric-oxide-dependent vasorelaxation. Can J Physiol Pharmacol 2018; 96:719-727. [PMID: 29430946 DOI: 10.1139/cjpp-2017-0477] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The endothelium is crucial for the maintenance of vascular tone by releasing several vasoactive substances, including nitric oxide (NO). Systemic mean arterial pressure is primarily regulated by the resistance vasculature, which has been shown to exhibit increased vascular reactivity, and decreased vasorelaxation during hypertension. Here, we aimed to determine the mechanism for mesenteric artery vasorelaxation of the stroke-prone spontaneously hypertensive rat (SHRSP). We hypothesized that endothelial NO synthase (eNOS) is upregulated in SHRSP vessels, increasing NO production to compensate for the endothelial dysfunction. Concentration-response curves to acetylcholine (ACh) were performed in second-order mesenteric arteries; we observed decreased relaxation responses to ACh (maximum effect elicited by the agonist) as compared with Wistar-Kyoto (WKY) controls. Vessels from SHRSP incubated with Nω-nitro-l-arginine methyl ester and (or) indomethacin exhibited decreased ACh-mediated relaxation, suggesting a primary role for NO-dependent relaxation. Vessels from SHRSP exhibited a significantly decreased relaxation response with inducible NO synthase (iNOS) inhibition, as compared with WKY vessels. Western blot analysis showed increased total phosphorylated NF-κB, and phosphorylated and total eNOS in SHRSP vessels. Overall, these data suggest a compensatory role for NO by increased eNOS activation. Moreover, we believe that iNOS, although increasing NO bioavailability to compensate for decreased relaxation, leads to a cycle of further endothelial dysfunction in SHRSP mesenteric arteries.
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Affiliation(s)
- Brandi M Wynne
- a Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.,b Department of Medicine, Nephrology, Emory University, Atlanta, GA 30322, USA
| | - Hicham Labazi
- a Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.,c Center for Cardiovascular Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Victor V Lima
- a Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.,d Institute of Biological Sciences and Health, Federal University of Mato Grosso - Barra do Garças - MT - Brazil; 78600-000
| | - Fernando S Carneiro
- a Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.,e Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil; 14049-900
| | - R Clinton Webb
- a Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Rita C Tostes
- a Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.,e Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil; 14049-900
| | - Fernanda R Giachini
- a Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.,d Institute of Biological Sciences and Health, Federal University of Mato Grosso - Barra do Garças - MT - Brazil; 78600-000
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Bondarenko AI, Panasiuk O, Okhai I, Montecucco F, Brandt KJ, Mach F. Ca 2+-dependent potassium channels and cannabinoid signaling in the endothelium of apolipoprotein E knockout mice before plaque formation. J Mol Cell Cardiol 2018; 115:54-63. [PMID: 29305938 DOI: 10.1016/j.yjmcc.2018.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 12/30/2017] [Accepted: 01/02/2018] [Indexed: 01/06/2023]
Abstract
Endothelial Ca2+-dependent K+ channels (KCa) regulate endothelial function. We also know that stimulation of type 2 cannabinoid (CB2) receptors ameliorates atherosclerosis. However, whether atherosclerosis is accompanied by altered endothelial KCa- and CB2 receptor-dependent signaling is unknown. By utilizing an in situ patch-clamp approach, we directly evaluated the KCa channel function and the CB2 receptor-dependent electrical responses in the endothelium of aortic strips from young ApoE-/- and C57Bl/6 mice. In the ApoE-/- group, the resting membrane potential (-30.1±1.1mV) was less negative (p<0.05) compared to WT (-38.9±1.4mV) and voltage ramps generated an overall KCa current of reduced amplitude. The peak hyperpolarization to 2μM Ach was not different between the groups. However, the sustained component was significantly reduced in ApoE-/- strips. In contrast, the peak hyperpolarization to 0.2μM Ach was increased in the ApoE-/- group, and SKA-31, a direct IKCa/SKCa channel opener, produced a hyperpolarization and whole-cell current of greater amplitude. The BKCa opener NS1619 produced hyperpolarization that was enhanced in ApoE-/- group. N-arachidonoyl glycine, a BKCa opener, produced a hyperpolarization of enhanced amplitude in ApoE-/- arteries. Selective CB2 receptor agonist AM1241 (5μM) had no effect on endothelial membrane potential in WT group; however, in ApoE-/- group, it elicited hyperpolarization that was inhibited by a selective CB2 receptor antagonist AM630. Conclusively, our data point to functional down-regulation of basal IKCa activity in unstimulated endothelium of ApoE-/- mice. Direct and indirect IKCa stimulation resulted in increased recruitment of the channels. In addition, our data point to up-regulation of endothelial BKCa channels and CB2 receptors in ApoE-/- arteries.
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Affiliation(s)
- Alexander I Bondarenko
- Circulatory Physiology Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz Str.4, 01024 Kiev, Ukraine.
| | - Olga Panasiuk
- Circulatory Physiology Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz Str.4, 01024 Kiev, Ukraine
| | - Iryna Okhai
- Circulatory Physiology Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz Str.4, 01024 Kiev, Ukraine
| | - Fabrizio Montecucco
- First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 viale Benedetto XV, 16132 Genoa, Italy; Ospedale Policlinico San Martino, largo Benzi 10, 16132 Genoa, Italy; Centre of Excellence for Biomedical Research (CEBR), University of Genoa, 9 viale Benedetto XV, 16132 Genoa, Italy
| | - Karim J Brandt
- Division of Cardiology, Foundation for Medical Researches, Department of Internal Medicine, University of Geneva, Av. de la Roseraie 64, CH -1211 Geneva, 4, Switzerland
| | - François Mach
- Division of Cardiology, Foundation for Medical Researches, Department of Internal Medicine, University of Geneva, Av. de la Roseraie 64, CH -1211 Geneva, 4, Switzerland
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Goto K, Ohtsubo T, Kitazono T. Endothelium-Dependent Hyperpolarization (EDH) in Hypertension: The Role of Endothelial Ion Channels. Int J Mol Sci 2018; 19:E315. [PMID: 29361737 PMCID: PMC5796258 DOI: 10.3390/ijms19010315] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 12/28/2022] Open
Abstract
Upon stimulation with agonists and shear stress, the vascular endothelium of different vessels selectively releases several vasodilator factors such as nitric oxide and prostacyclin. In addition, vascular endothelial cells of many vessels regulate the contractility of the vascular smooth muscle cells through the generation of endothelium-dependent hyperpolarization (EDH). There is a general consensus that the opening of small- and intermediate-conductance Ca2+-activated K⁺ channels (SKCa and IKCa) is the initial mechanistic step for the generation of EDH. In animal models and humans, EDH and EDH-mediated relaxations are impaired during hypertension, and anti-hypertensive treatments restore such impairments. However, the underlying mechanisms of reduced EDH and its improvement by lowering blood pressure are poorly understood. Emerging evidence suggests that alterations of endothelial ion channels such as SKCa channels, inward rectifier K⁺ channels, Ca2+-activated Cl- channels, and transient receptor potential vanilloid type 4 channels contribute to the impaired EDH during hypertension. In this review, we attempt to summarize the accumulating evidence regarding the pathophysiological role of endothelial ion channels, focusing on their relationship with EDH during hypertension.
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Affiliation(s)
- Kenichi Goto
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
| | - Toshio Ohtsubo
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
| | - Takanari Kitazono
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
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Behringer EJ, Segal SS. Impact of Aging on Calcium Signaling and Membrane Potential in Endothelium of Resistance Arteries: A Role for Mitochondria. J Gerontol A Biol Sci Med Sci 2017; 72:1627-1637. [PMID: 28510636 DOI: 10.1093/gerona/glx079] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/21/2017] [Indexed: 12/20/2022] Open
Abstract
Impaired blood flow to peripheral tissues during advanced age is associated with endothelial dysfunction and diminished bioavailability of nitric oxide (NO). However, it is unknown whether aging impacts coupling between intracellular calcium ([Ca2+]i) signaling and small- and intermediate K+ channel (SKCa/IKCa) activity during endothelium-derived hyperpolarization (EDH), a signaling pathway integral to dilation of the resistance vasculature. To address the potential impact of aging on EDH, Fura-2 photometry and intracellular recording were applied to evaluate [Ca2+]i and membrane potential of intact endothelial tubes (width, 60 µm; length, 1-3 mm) freshly isolated from superior epigastric arteries of young (4-6 mo) and old (24-26 mo) male C57BL/6 mice. In response to acetylcholine, intracellular release of Ca2+ from the endoplasmic reticulum (ER) was enhanced with aging. Further, treatment with the mitochondrial uncoupler FCCP evoked a significant increase of [Ca2+]i with membrane hyperpolarization in an SKCa/IKCa-dependent manner in the endothelium of old but not young mice. We conclude that the ability of resistance artery endothelium to release Ca2+ from intracellular stores (ie, ER and mitochondria) and hyperpolarize Vm via SKCa/IKCa activation is augmented as compensation for reduced NO bioavailability during advanced age.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, Loma Linda University, California.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia.,Dalton Cardiovascular Research Center, Columbia, Missouri
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17
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Kloza M, Baranowska-Kuczko M, Malinowska B, Karpińska O, Harasim-Symbor E, Kasacka I, Kozłowska H. The influence of DOCA-salt hypertension and chronic administration of the FAAH inhibitor URB597 on KCa2.3/KCa3.1-EDH-type relaxation in rat small mesenteric arteries. Vascul Pharmacol 2017; 99:65-73. [DOI: 10.1016/j.vph.2017.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 10/02/2017] [Accepted: 10/11/2017] [Indexed: 10/18/2022]
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18
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Karpińska O, Baranowska-Kuczko M, Malinowska B, Kloza M, Kusaczuk M, Gęgotek A, Golec P, Kasacka I, Kozłowska H. Mechanisms of l-alpha-lysophosphatidylinositol-induced relaxation in human pulmonary arteries. Life Sci 2017; 192:38-45. [PMID: 29155298 DOI: 10.1016/j.lfs.2017.11.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 11/11/2017] [Accepted: 11/15/2017] [Indexed: 01/13/2023]
Abstract
AIMS l-Alpha-lysophosphatidylinositol (LPI) is an endogenous agonist of G protein-coupled receptor 55 (GPR55) which relaxes mesenteric arteries on activation. The aim of the present study was to determine the influence and underlying mechanisms of LPI-induced relaxation in human pulmonary arteries (hPAs). MAIN METHODS Functional studies were performed in isolated hPAs using organ bath technique. The expression of GPR55 in hPAs and bronchioles was determined by real-time qPCR, Western blot analysis, and immunohistochemistry. KEY FINDINGS LPI induced a concentration-dependent vasorelaxation in endothelium-intact hPAs. This effect was attenuated by the GPR55 antagonist CID16020046, the peroxisome proliferator-activated receptor-γ (PPARγ) antagonist GW9662, the putative endothelial cannabinoid receptor (CBe) antagonist O-1918 and the inhibitor of nitric oxide (NO) synthase (L-NAME). In addition, vasorelaxation was also attenuated by the presence of a high KCl concentration, selective blockers of small (KCa2.3; UCL1684), intermediate (KCa3.1; TRAM-34) and large conductance (KCa1.1; iberiotoxin) calcium-activated potassium channels and by endothelium denudation. However, vasorelaxation was not attenuated by the cannabinoid CB1 receptor antagonist AM251 or by the cyclooxygenase inhibitor indomethacin. SIGNIFICANCE The study showed that the LPI-induced vasorelaxation was endothelium-dependent and mediated by GPR55, PPARγ and CBe receptors, occurred in a NO- and calcium-activated potassium channel-dependent manner in isolated hPAs. LPI seems to possess positive, hypotensive properties in pulmonary vascular bed.
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Affiliation(s)
- Olga Karpińska
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Mickiewicza Str. 2A, 15-089 Białystok, Poland.
| | - Marta Baranowska-Kuczko
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Mickiewicza Str. 2A, 15-089 Białystok, Poland
| | - Barbara Malinowska
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Mickiewicza Str. 2A, 15-089 Białystok, Poland
| | - Monika Kloza
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Mickiewicza Str. 2A, 15-089 Białystok, Poland
| | - Magdalena Kusaczuk
- Department of Pharmaceutical Biochemistry, Medical University of Białystok, Mickiewicza Str. 2A, 15-089 Białystok, Poland
| | - Agnieszka Gęgotek
- Department of Inorganic and Analytical Chemistry, Medical University of Białystok, Mickiewicza Str. 2D, 15-222 Białystok, Poland
| | - Paweł Golec
- Department of Thoracic Surgery, Medical University of Białystok, M. Skłodowskiej-Curie Str. 24A, 15-276 Białystok, Poland
| | - Irena Kasacka
- Department of Histology and Cytophysiology, Medical University of Białystok, Mickiewicza Str. 2C, 15-222 Białystok, Poland
| | - Hanna Kozłowska
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Mickiewicza Str. 2A, 15-089 Białystok, Poland
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Salomonsson M, Brasen JC, Sorensen CM. Role of renal vascular potassium channels in physiology and pathophysiology. Acta Physiol (Oxf) 2017; 221:14-31. [PMID: 28371470 DOI: 10.1111/apha.12882] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/10/2016] [Accepted: 03/22/2017] [Indexed: 12/31/2022]
Abstract
The control of renal vascular tone is important for the regulation of salt and water balance, blood pressure and the protection against damaging elevated glomerular pressure. The K+ conductance is a major factor in the regulation of the membrane potential (Vm ) in vascular smooth muscle (VSMC) and endothelial cells (EC). The vascular tone is controlled by Vm via its effect on the opening probability of voltage-operated Ca2+ channels (VOCC) in VSMC. When K+ conductance increases Vm becomes more negative and vasodilation follows, while deactivation of K+ channels leads to depolarization and vasoconstriction. K+ channels in EC indirectly participate in the control of vascular tone by endothelium-derived vasodilation. Therefore, by regulating the tone of renal resistance vessels, K+ channels have a potential role in the control of fluid homoeostasis and blood pressure as well as in the protection of the renal parenchyma. The main classes of K+ channels (calcium activated (KCa ), inward rectifier (Kir ), voltage activated (Kv ) and ATP sensitive (KATP )) have been found in the renal vessels. In this review, we summarize results available in the literature and our own studies in the field. We compare the ambiguous in vitro and in vivo results. We discuss the role of single types of K+ channels and the integrated function of several classes. We also deal with the possible role of renal vascular K+ channels in the pathophysiology of hypertension, diabetes mellitus and sepsis.
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Affiliation(s)
| | - J. C. Brasen
- Department of Electrical Engineering; Technical University of Denmark; Kgs. Lyngby Denmark
| | - C. M. Sorensen
- Department of Biomedical Sciences; Division of Renal and Vascular Physiology; University of Copenhagen; Copenhagen Denmark
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20
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Leung SWS, Vanhoutte PM. Endothelium-dependent hyperpolarization: age, gender and blood pressure, do they matter? Acta Physiol (Oxf) 2017; 219:108-123. [PMID: 26548576 DOI: 10.1111/apha.12628] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 09/21/2015] [Accepted: 11/02/2015] [Indexed: 12/14/2022]
Abstract
Under physiological conditions, the endothelium generates vasodilator signals [prostacyclin, nitric oxide NO and endothelium-dependent hyperpolarization (EDH)], for the regulation of vascular tone. The relative importance of these two signals depends on the diameter of the blood vessels: as the diameter of the arteries decreases, the contribution of EDH to the regulation of vascular tone increases. The mechanism involved in EDH varies with species and blood vessel types; nevertheless, activation of endothelial intermediate- and small-conductance calcium-activated potassium channels (IKCa and SKCa , respectively) is characteristic of the EDH pathway. IKCa - and SKCa -mediated EDH are reduced with endothelial dysfunction, which develops with ageing and hypertension, and is less pronounced in female than in age-matched male until after menopause. Impaired EDH-mediated relaxation is related to a reduced involvement of SKCa , so that the response becomes more dependent on IKCa . The latter depends on the activation of adenosine monophosphate-activated protein kinase (AMPK) and silent information regulator T1 (SIRT1), proteins associated with the process of cellular senescence and vascular signalling in response to the female hormone. An understanding of the role of AMPK and/or SIRT1 in EDH-like responses may help identifying effective pharmacological strategies to prevent the development of vascular complications of different aetiologies.
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Affiliation(s)
- S. W. S. Leung
- Department of Pharmacology & Pharmacy; University of Hong Kong; Hong Kong Hong Kong SAR China
| | - P. M. Vanhoutte
- Department of Pharmacology & Pharmacy; University of Hong Kong; Hong Kong Hong Kong SAR China
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Seki T, Goto K, Kiyohara K, Kansui Y, Murakami N, Haga Y, Ohtsubo T, Matsumura K, Kitazono T. Downregulation of Endothelial Transient Receptor Potential Vanilloid Type 4 Channel and Small-Conductance of Ca2+-Activated K+ Channels Underpins Impaired Endothelium-Dependent Hyperpolarization in Hypertension. Hypertension 2016; 69:143-153. [PMID: 27872234 DOI: 10.1161/hypertensionaha.116.07110] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/01/2016] [Accepted: 10/31/2016] [Indexed: 01/24/2023]
Abstract
Endothelium-dependent hyperpolarization (EDH)-mediated responses are impaired in hypertension, but the underlying mechanisms have not yet been determined. The activation of small- and intermediate-conductance of Ca2+-activated K+ channels (SKCa and IKCa) underpins EDH-mediated responses. It was recently reported that Ca2+ influx through endothelial transient receptor potential vanilloid type 4 channel (TRPV4) is a prerequisite for the activation of SKCa/IKCa in endothelial cells in specific beds. Here, we attempted to determine whether the impairment of EDH in hypertension is attributable to the dysfunction of TRPV4 and S/IKCa, using isolated superior mesenteric arteries of 20-week-old stroke-prone spontaneously hypertensive rats (SHRSP) and age-matched Wistar-Kyoto (WKY) rats. In the WKY arteries, EDH-mediated responses were reduced by a combination of SKCa/IKCa blockers (apamin plus TRAM-34; 1-[(2-chlorophenyl)diphenylmethl]-1H-pyrazole) and by the blockade of TRPV4 with the selective antagonist RN-1734 or HC-067047. In the SHRSP arteries, EDH-mediated hyperpolarization and relaxation were significantly impaired when compared with WKY. GSK1016790A, a selective TRPV4 activator, evoked robust hyperpolarization and relaxation in WKY arteries. In contrast, in SHRSP arteries, the GSK1016790A-evoked hyperpolarization was small and relaxation was absent. Hyperpolarization and relaxation to cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine, a selective SKCa activator, were marginally decreased in SHRSP arteries compared with WKY arteries. The expression of endothelial TRPV4 and SKCa protein was significantly decreased in the SHRSP mesenteric arteries compared with those of WKY, whereas function and expression of IKCa were preserved in SHRSP arteries. These findings suggest that EDH-mediated responses are impaired in superior mesenteric arteries of SHRSP because of a reduction in both TRPV4 and SKCa input to EDH.
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Affiliation(s)
- Takunori Seki
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kenichi Goto
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
| | - Kanako Kiyohara
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yasuo Kansui
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Noboru Murakami
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshie Haga
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshio Ohtsubo
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kiyoshi Matsumura
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takanari Kitazono
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Choi S, Kim JA, Li H, Shin K, Oh GT, Lee Y, Oh S, Pewzner‐Jung Y, Futerman AH, Suh SH. KCa 3.1 upregulation preserves endothelium-dependent vasorelaxation during aging and oxidative stress. Aging Cell 2016; 15:801-10. [PMID: 27363720 PMCID: PMC5013018 DOI: 10.1111/acel.12502] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2016] [Indexed: 01/24/2023] Open
Abstract
Endothelial oxidative stress develops with aging and reactive oxygen species impair endothelium-dependent relaxation (EDR) by decreasing nitric oxide (NO) availability. Endothelial KCa 3.1, which contributes to EDR, is upregulated by H2 O2 . We investigated whether KCa 3.1 upregulation compensates for diminished EDR to NO during aging-related oxidative stress. Previous studies identified that the levels of ceramide synthase 5 (CerS5), sphingosine, and sphingosine 1-phosphate were increased in aged wild-type and CerS2 mice. In primary mouse aortic endothelial cells (MAECs) from aged wild-type and CerS2 null mice, superoxide dismutase (SOD) was upregulated, and catalase and glutathione peroxidase 1 (GPX1) were downregulated, when compared to MAECs from young and age-matched wild-type mice. Increased H2 O2 levels induced Fyn and extracellular signal-regulated kinases (ERKs) phosphorylation and KCa 3.1 upregulation. Catalase/GPX1 double knockout (catalase(-/-) /GPX1(-/-) ) upregulated KCa 3.1 in MAECs. NO production was decreased in aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) MAECs. However, KCa 3.1 activation-induced, N(G) -nitro-l-arginine-, and indomethacin-resistant EDR was increased without a change in acetylcholine-induced EDR in aortic rings from aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) mice. CerS5 transfection or exogenous application of sphingosine or sphingosine 1-phosphate induced similar changes in levels of the antioxidant enzymes and upregulated KCa 3.1. Our findings suggest that, during aging-related oxidative stress, SOD upregulation and downregulation of catalase and GPX1, which occur upon altering the sphingolipid composition or acyl chain length, generate H2 O2 and thereby upregulate KCa 3.1 expression and function via a H2 O2 /Fyn-mediated pathway. Altogether, enhanced KCa 3.1 activity may compensate for decreased NO signaling during vascular aging.
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Affiliation(s)
- Shinkyu Choi
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Ji Aee Kim
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Hai‐yan Li
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Kyong‐Oh Shin
- College of Pharmacy and MRC Chungbuk National University Chongju South Korea
| | - Goo Taeg Oh
- Department of Life Sciences Ewha Womans University Seoul South Korea
| | - Yong‐Moon Lee
- College of Pharmacy and MRC Chungbuk National University Chongju South Korea
| | - Seikwan Oh
- Department of Molecular Medicine Medical School Ewha Womans University Seoul South Korea
| | - Yael Pewzner‐Jung
- Department of Biological Chemistry Weizmann Institute of Science Rehovot Israel
| | - Anthony H. Futerman
- Department of Biological Chemistry Weizmann Institute of Science Rehovot Israel
| | - Suk Hyo Suh
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
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24
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Köhler R, Oliván-Viguera A, Wulff H. Endothelial Small- and Intermediate-Conductance K Channels and Endothelium-Dependent Hyperpolarization as Drug Targets in Cardiovascular Disease. ADVANCES IN PHARMACOLOGY 2016; 77:65-104. [DOI: 10.1016/bs.apha.2016.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Kong BWC, Man RYK, Gao Y, Vanhoutte PM, Leung SWS. Reduced activity of SKC a and Na-K ATPase underlies the accelerated impairment of EDH-type relaxations in mesenteric arteries of aging spontaneously hypertensive rats. Pharmacol Res Perspect 2015; 3:e00150. [PMID: 26171229 PMCID: PMC4492766 DOI: 10.1002/prp2.150] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 04/16/2015] [Indexed: 02/06/2023] Open
Abstract
Aging is accompanied by endothelial dysfunction due to reduced bioavailability of nitric oxide (NO) and/or reduced endothelium-dependent hyperpolarizations (EDH). This study examines the hypothesis that hypertension aggravates the impairment of EDH-type relaxation due to aging. EDH-type relaxations were studied in superior mesenteric arteries isolated from Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats of 12, 36, 60, and 72 weeks of age. EDH-type relaxations in WKY were reduced with aging, and this was associated with an impairment of the function of small-conductance calcium-activated potassium channels (SKCa) and sodium-potassium ATPase (Na-K ATPase). EDH-type relaxation in SHR was smaller than that in WKY arteries, and further reduction occurred with aging. Pharmacological experiments suggested a reduced involvement of SKCa and Na-K ATPase and activation of adenosine monophosphate-activated protein kinase and silent information regulator T1 (sirtuin-1; SIRT1) in mesenteric arteries of 12-week-old SHR. These pharmacological findings suggest that in superior mesenteric arteries of the rat, the reduction in EDH-type relaxation occurs with aging and that such a reduction is exacerbated in hypertension. The latter exacerbation appears to involve proteins associated with the process of cellular senescence and is related to impaired function of SKCa and Na-K ATPase, a phenomenon that is also observed in mesenteric arteries of older normotensive rats.
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Affiliation(s)
- Billy W C Kong
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong Hong Kong SAR, China
| | - Ricky Y K Man
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong Hong Kong SAR, China
| | - Yuansheng Gao
- Department of Physiology and Pathophysiology, Peking University Health Science Center Beijing, China
| | - Paul M Vanhoutte
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong Hong Kong SAR, China
| | - Susan W S Leung
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong Hong Kong SAR, China
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Sonkusare SK, Dalsgaard T, Bonev AD, Hill-Eubanks DC, Kotlikoff MI, Scott JD, Santana LF, Nelson MT. AKAP150-dependent cooperative TRPV4 channel gating is central to endothelium-dependent vasodilation and is disrupted in hypertension. Sci Signal 2014; 7:ra66. [PMID: 25005230 DOI: 10.1126/scisignal.2005052] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Endothelial cell dysfunction, characterized by a diminished response to endothelial cell-dependent vasodilators, is a hallmark of hypertension. TRPV4 channels play a major role in endothelial-dependent vasodilation, a function mediated by local Ca(2+) influx through clusters of functionally coupled TRPV4 channels rather than by a global increase in endothelial cell Ca(2+). We showed that stimulation of muscarinic acetylcholine receptors on endothelial cells of mouse arteries exclusively activated TRPV4 channels that were localized at myoendothelial projections (MEPs), specialized regions of endothelial cells that contact smooth muscle cells. Muscarinic receptor-mediated activation of TRPV4 depended on protein kinase C (PKC) and the PKC-anchoring protein AKAP150, which was concentrated at MEPs. Cooperative opening of clustered TRPV4 channels specifically amplified Ca(2+) influx at MEPs. Cooperativity of TRPV4 channels at non-MEP sites was much lower, and cooperativity at MEPs was greatly reduced by chelation of intracellular Ca(2+) or AKAP150 knockout, suggesting that Ca(2+) entering through adjacent channels underlies the AKAP150-dependent potentiation of TRPV4 activity. In a mouse model of angiotensin II-induced hypertension, MEP localization of AKAP150 was disrupted, muscarinic receptor stimulation did not activate TRPV4 channels, cooperativity among TRPV4 channels at MEPs was weaker, and vasodilation in response to muscarinic receptor stimulation was reduced. Thus, endothelial-dependent dilation of resistance arteries is enabled by MEP-localized AKAP150, which ensures the proximity of PKC to TRPV4 channels and the coupled channel gating necessary for efficient communication from endothelial to smooth muscle cells in arteries. Disruption of this molecular assembly may contribute to altered blood flow in hypertension.
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Affiliation(s)
- Swapnil K Sonkusare
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA
| | - Thomas Dalsgaard
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA
| | - Adrian D Bonev
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA
| | - David C Hill-Eubanks
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA
| | - Michael I Kotlikoff
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - John D Scott
- Howard Hughes Medical Institute and Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Luis F Santana
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Mark T Nelson
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA. Institute of Cardiovascular Sciences, University of Manchester, Manchester M13 9NT, UK.
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Waeckel L, Bertin F, Clavreul N, Damery T, Köhler R, Paysant J, Sansilvestri-Morel P, Simonet S, Vayssettes-Courchay C, Wulff H, Verbeuren TJ, Félétou M. Preserved regulation of renal perfusion pressure by small and intermediate conductance KCa channels in hypertensive mice with or without renal failure. Pflugers Arch 2014; 467:817-31. [DOI: 10.1007/s00424-014-1542-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 05/19/2014] [Accepted: 05/19/2014] [Indexed: 11/29/2022]
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Musa MG, Torrens C, Clough GF. The microvasculature: a target for nutritional programming and later risk of cardio-metabolic disease. Acta Physiol (Oxf) 2014; 210:31-45. [PMID: 23758932 DOI: 10.1111/apha.12131] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 04/03/2013] [Accepted: 06/03/2013] [Indexed: 12/25/2022]
Abstract
There is compelling evidence that microvascular deficits affecting multiple tissues and organs play an important role in the aetiopathogenesis of cardio-metabolic disease. Furthermore, both in humans and animal models, deficits in small vessel structure and function can be detected early, often before the onset of macrovascular disease and the development of end-organ damage that is common to hypertension and obesity-associated clinical disorders. This article considers the growing evidence for the negative impact of an adverse maternal diet on the long-term health of her child, and how this can result in a disadvantageous vascular phenotype that extends to the microvascular bed. We describe how structural and functional modifications in the offspring microcirculation during development may represent an important and additional risk determinant to increase susceptibility to the development of cardio-metabolic disease in adult life and consider the cell-signalling pathways associated with endothelial dysfunction that may be 'primed' by the maternal environment. Published studies were identified that reported outcomes related to the microcirculation, endothelium, maternal diet and vascular programming using NCBI PubMed.gov, MEDLINE and ISI Web of Science databases from 1980 until April 2013 using pre-specified search terms. Information extracted from over 230 original reports and review articles was critically evaluated by the authors for inclusion in this review.
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Affiliation(s)
- M. G. Musa
- Vascular Research Group; Human Development and Health; Faculty of Medicine; University of Southampton; Southampton UK
| | - C. Torrens
- Vascular Research Group; Human Development and Health; Faculty of Medicine; University of Southampton; Southampton UK
| | - G. F. Clough
- Vascular Research Group; Human Development and Health; Faculty of Medicine; University of Southampton; Southampton UK
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Enouri S, Monteith G, Johnson R. Effects of acute transmural pressure elevation on endothelium-dependent vasodilation in isolated rat mesenteric veins. J Vasc Res 2013; 51:27-36. [PMID: 24280957 DOI: 10.1159/000356322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 09/29/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The vascular regulatory function of the endothelium can be impaired by increases in transmural pressure (TMP). We tested the hypothesis that increasing TMP impairs the endothelial dilator function of rat mesenteric small veins (MSVs). METHODS In PGF2α-preconstricted MSVs, bradykinin (BK), sodium nitroprusside (SNP) and S-Nitroso-N-acetylpenicillamine (SNAP) concentration-response curves were generated at intermediate (6 mm Hg) and high (12 mm Hg) pressures. BK-induced vasodilation was examined in the absence and presence of nitric oxide synthase inhibitor [N(ω)-nitro-L-arginine (L-NNA), 100 µM], cyclooxygenase inhibitor (indomethacin, 1 µM), and large (BKCa, paxilline, 500 nM) and small (SKCa, apamin, 300 nM) conductance Ca(2+)-activated K(+) channel blockers. RESULTS BK, SNP and SNAP responses were not altered by TMP increases. BK-induced vasodilation was significantly reduced by L-NNA, indomethacin, apamin and paxilline at 6 mm Hg and L-NNA at 12 mm Hg, and was further reduced by coapplication of apamin and/or paxilline with L-NNA compared with responses obtained with either blocker. Endothelium removal completely abolished BK-induced vasodilation. CONCLUSION Venous endothelial dilator function is not affected by TMP elevation. BK-induced vasodilation is completely dependent on the presence of functional endothelial cells and mediated in part by nitric oxide, BKCa and SKCa channels, while the participation of prostacyclin may be important at intermediate pressures.
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Affiliation(s)
- Saad Enouri
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ont., Canada
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Mendes RT, Sordi R, Olchanheski LR, Machado WM, Stanczyk CP, Assreuy J, Santos FA, Fernandes D. Periodontitis increases vascular cyclooxygenase-2: potential effect on vascular tone. J Periodontal Res 2013; 49:85-92. [DOI: 10.1111/jre.12083] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2013] [Indexed: 11/30/2022]
Affiliation(s)
- R. T. Mendes
- Department of Dentistry; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - R. Sordi
- Department of Pharmacology; Universidade Federal de Santa Catarina; Florianópolis SC Brazil
| | - L. R. Olchanheski
- Department of Pharmaceutical Sciences; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - W. M. Machado
- Department of Pharmaceutical Sciences; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - C. P. Stanczyk
- Department of Dentistry; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - J. Assreuy
- Department of Pharmacology; Universidade Federal de Santa Catarina; Florianópolis SC Brazil
| | - F. A. Santos
- Department of Dentistry; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - D. Fernandes
- Department of Pharmaceutical Sciences; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
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Pires PW, Dams Ramos CM, Matin N, Dorrance AM. The effects of hypertension on the cerebral circulation. Am J Physiol Heart Circ Physiol 2013; 304:H1598-614. [PMID: 23585139 DOI: 10.1152/ajpheart.00490.2012] [Citation(s) in RCA: 250] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Maintenance of brain function depends on a constant blood supply. Deficits in cerebral blood flow are linked to cognitive decline, and they have detrimental effects on the outcome of ischemia. Hypertension causes alterations in cerebral artery structure and function that can impair blood flow, particularly during an ischemic insult or during periods of low arterial pressure. This review will focus on the historical discoveries, novel developments, and knowledge gaps in 1) hypertensive cerebral artery remodeling, 2) vascular function with emphasis on myogenic reactivity and endothelium-dependent dilation, and 3) blood-brain barrier function. Hypertensive artery remodeling results in reduction in the lumen diameter and an increase in the wall-to-lumen ratio in most cerebral arteries; this is linked to reduced blood flow postischemia and increased ischemic damage. Many factors that are increased in hypertension stimulate remodeling; these include the renin-angiotensin-aldosterone system and reactive oxygen species levels. Endothelial function, vital for endothelium-mediated dilation and regulation of myogenic reactivity, is impaired in hypertension. This is a consequence of alterations in vasodilator mechanisms involving nitric oxide, epoxyeicosatrienoic acids, and ion channels, including calcium-activated potassium channels and transient receptor potential vanilloid channel 4. Hypertension causes blood-brain barrier breakdown by mechanisms involving inflammation, oxidative stress, and vasoactive circulating molecules. This exposes neurons to cytotoxic molecules, leading to neuronal loss, cognitive decline, and impaired recovery from ischemia. As the population ages and the incidence of hypertension, stroke, and dementia increases, it is imperative that we gain a better understanding of the control of cerebral artery function in health and disease.
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Affiliation(s)
- Paulo W Pires
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
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Simonet S, Isabelle M, Bousquenaud M, Clavreul N, Félétou M, Vayssettes-Courchay C, Verbeuren TJ. KCa 3.1 channels maintain endothelium-dependent vasodilatation in isolated perfused kidneys of spontaneously hypertensive rats after chronic inhibition of NOS. Br J Pharmacol 2013; 167:854-67. [PMID: 22646737 DOI: 10.1111/j.1476-5381.2012.02062.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The purpose of the study was to investigate renal endothelium-dependent vasodilatation in a model of severe hypertension associated with kidney injury. EXPERIMENTAL APPROACH Changes in perfusion pressure were measured in isolated, perfused kidneys taken from 18-week-old Wistar-Kyoto rat (WKY), spontaneously hypertensive rats (SHR) and SHR treated for 2 weeks with N(ω) -nitro-L-arginine methyl ester in the drinking water (L-NAME-treated SHR, 6 mg·kg(-1) ·day(-1) ). KEY RESULTS Acetylcholine caused similar dose-dependent renal dilatation in the three groups. In vitro administration of indomethacin did not alter the vasodilatation, while the addition of N(w) -nitro-L-arginine (L-NA) produced a differential inhibition of the vasodilatation, (inhibition in WKY > SHR > L-NAME-treated SHR). Further addition of ODQ, an inhibitor of soluble guanylyl cyclase, abolished the responses to sodium nitroprusside but did not affect the vasodilatation to acetylcholine. However, the addition of TRAM-34 (or charybdotoxin) inhibitors of Ca(2+) -activated K(+) channels of intermediate conductance (K(Ca) 3.1), blocked the vasodilatation to acetylcholine, while apamin, an inhibitor of Ca(2+) -activated K(+) channels of small conductance (K(Ca) 2.3), was ineffective. Dilatation induced by an opener of K(Ca) 3.1/K(Ca) 2.3 channels, NS-309, was also blocked by TRAM-34, but not by apamin. The magnitude and duration of NS-309-induced vasodilatation and the renal expression of mRNA for K(Ca) 3.1, but not K(Ca) 2.3, channels followed the same ranking order (WKY < SHR < L-NAME-treated SHR). CONCLUSIONS AND IMPLICATIONS In SHR kidneys, an EDHF-mediated response, involving activation of K(Ca) 3.1 channels, contributed to the mechanism of endothelium-dependent vasodilatation. In kidneys from L-NAME-treated SHR, up-regulation of this pathway fully compensated for the decrease in NO availability.
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Tawa M, Shimosato T, Geddawy A, Imamura T, Okamura T. Influence of Hypoxia on Endothelium-Derived NO-Mediated Relaxation in Rat Carotid, Mesenteric and Iliac Arteries. Pharmacology 2013; 91:322-30. [DOI: 10.1159/000351706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 03/19/2013] [Indexed: 11/19/2022]
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Abstract
The present review first summarizes the complex chain of events, in endothelial and vascular smooth muscle cells, that leads to endothelium-dependent relaxations (vasodilatations) due to the generation of nitric oxide (NO) by endothelial nitric oxide synthase (eNOS) and how therapeutic interventions may improve the bioavailability of NO and thus prevent/cure endothelial dysfunction. Then, the role of other endothelium-derived mediators (endothelium-derived hyperpolarizing (EDHF) and contracting (EDCF) factors, endothelin-1) and signals (myoendothelial coupling) is summarized also, with special emphasis on their interaction(s) with the NO pathway, which make the latter not only a major mediator but also a key regulator of endothelium-dependent responses.
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Damkjaer M, Nielsen G, Bodendiek S, Staehr M, Gramsbergen JB, de Wit C, Jensen BL, Simonsen U, Bie P, Wulff H, Köhler R. Pharmacological activation of KCa3.1/KCa2.3 channels produces endothelial hyperpolarization and lowers blood pressure in conscious dogs. Br J Pharmacol 2012; 165:223-34. [PMID: 21699504 DOI: 10.1111/j.1476-5381.2011.01546.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE In rodents, the endothelial KCa channels, KCa3.1 and KCa2.3, have been shown to play a crucial role in initiating endothelium-derived hyperpolarizing factor (EDHF) vasodilator responses. However, it is not known to what extent these channels are involved in blood pressure regulation in large mammals, which would also allow us to address safety issues. We therefore characterized canine endothelial KCa3.1 and KCa2.3 functions and evaluated the effect of the KCa3.1/KCa2.3 activator SKA-31 on blood pressure and heart rate in dogs. EXPERIMENTAL APPROACH Canine endothelial KCa3.1/KCa2.3 functions were studied by patch-clamp electrophysiology and wire myography in mesenteric arteries. Systemic cardiovascular actions of acute SKA-31 administration were monitored in conscious, unstressed beagle dogs. KEY RESULTS Mesenteric endothelial cells expressed functional KCa3.1 and KCa2.3 channels that were strongly activated by SKA-31. SKA-31 hyperpolarized the endothelial membrane and doubled endothelial hyperpolarization-dependent vasodilator responses in mesenteric arteries. SKA-31 (2 mg·kg(-1), i.v.) rapidly decreased the MAP by 28 ± 6 mmHg; this response was transient (8 ± 1 s), and the initial drop was followed by a fast and pronounced increase in HR (+109 ± 7 beats min(-1)) reflecting baroreceptor activation. SKA-31 significantly augmented similar transient depressor responses elicited by ACh (20 ng·kg(-1)) and doubled the magnitude of the response over time. CONCLUSIONS AND IMPLICATIONS Activation of endothelial KCa3.1 and KCa2.3 lowers arterial blood pressure in dogs by an immediate electrical vasodilator mechanism. The results support the concept that pharmacological activation of these channels may represent a potential unique endothelium-specific antihypertensive therapy.
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Affiliation(s)
- Mads Damkjaer
- Cardiovascular and Renal Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
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Sorensen CM, Braunstein TH, Holstein-Rathlou NH, Salomonsson M. Role of vascular potassium channels in the regulation of renal hemodynamics. Am J Physiol Renal Physiol 2012; 302:F505-18. [DOI: 10.1152/ajprenal.00052.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
K+ conductance is a major determinant of membrane potential ( Vm) in vascular smooth muscle (VSMC) and endothelial cells (EC). The vascular tone is controlled by Vm through the action of voltage-operated Ca2+ channels (VOCC) in VSMC. Increased K+ conductance leads to hyperpolarization and vasodilation, while inactivation of K+ channels causes depolarization and vasoconstriction. K+ channels in EC indirectly participate in the control of vascular tone by several mechanisms, e.g., release of nitric oxide and endothelium-derived hyperpolarizing factor. In the kidney, a change in the activity of one or more classes of K+ channels will lead to a change in hemodynamic resistance and therefore of renal blood flow and glomerular filtration pressure. Through these effects, the activity of renal vascular K+ channels influences renal salt and water excretion, fluid homeostasis, and ultimately blood pressure. Four main classes of K+ channels [calcium activated (KCa), inward rectifier (Kir), voltage activated (KV), and ATP sensitive (KATP)] are found in the renal vasculature. Several in vitro experiments have suggested a role for individual classes of K+ channels in the regulation of renal vascular function. Results from in vivo experiments are sparse. We discuss the role of the different classes of renal vascular K+ channels and their possible role in the integrated function of the renal microvasculature. Since several pathological conditions, among them hypertension, are associated with alterations in K+ channel function, the role of renal vascular K+ channels in the control of salt and water excretion deserves attention.
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Affiliation(s)
- Charlotte Mehlin Sorensen
- Institute of Biomedical Sciences, Division of Renal and Vascuar Physiology, The Panum Institute, and
| | - Thomas Hartig Braunstein
- Danish National Research Foundation Center for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | | | - Max Salomonsson
- Institute of Biomedical Sciences, Division of Renal and Vascuar Physiology, The Panum Institute, and
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Gaete PS, Lillo MA, Ardiles NM, Pérez FR, Figueroa XF. Ca2+-activated K+ channels of small and intermediate conductance control eNOS activation through NAD(P)H oxidase. Free Radic Biol Med 2012; 52:860-70. [PMID: 22210378 DOI: 10.1016/j.freeradbiomed.2011.11.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 11/23/2011] [Accepted: 11/30/2011] [Indexed: 11/24/2022]
Abstract
Ca(2+)-activated K(+) channels (K(Ca)) and NO play a central role in the endothelium-dependent control of vasomotor tone. We evaluated the interaction of K(Ca) with NO production in isolated arterial mesenteric beds of the rat. In phenylephrine-contracted mesenteries, acetylcholine (ACh)-induced vasodilation was reduced by NO synthase (NOS) inhibition with N(ω)-nitro-L-arginine (L-NA), but in the presence of tetraethylammonium, L-NA did not further affect the response. In KCl-contracted mesenteries, the relaxation elicited by 100 nM ACh or 1 μM ionomycin was abolished by L-NA, tetraethylammonium, or simultaneous blockade of small-conductance K(Ca) (SK(Ca)) channels with apamin and intermediate-conductance K(Ca) (IK(Ca)) channels with triarylmethane-34 (TRAM-34). Apamin-TRAM-34 treatment also abolished 100 nM ACh-activated NO production, which was associated with an increase in superoxide formation. Endothelial cell Ca(2+) buffering with BAPTA elicited a similar increment in superoxide. Apamin-TRAM-34 treatment increased endothelial NOS phosphorylation at threonine 495 (P-eNOS(Thr495)). Blockade of NAD(P)H oxidase with apocynin or superoxide dismutation with PEG-SOD prevented the increment in superoxide and changes in P-eNOS(Thr495) observed during apamin and TRAM-34 application. Our results indicate that blockade of SK(Ca) and IK(Ca) activates NAD(P)H oxidase-dependent superoxide formation, which leads to inhibition of NO release through P-eNOS(Thr495). These findings disclose a novel mechanism involved in the control of NO production.
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Affiliation(s)
- Pablo S Gaete
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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Matsumoto T, Szasz T, Tostes RC, Webb RC. Impaired β-adrenoceptor-induced relaxation in small mesenteric arteries from DOCA-salt hypertensive rats is due to reduced K(Ca) channel activity. Pharmacol Res 2012; 65:537-45. [PMID: 22388053 DOI: 10.1016/j.phrs.2012.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 02/07/2012] [Accepted: 02/14/2012] [Indexed: 10/28/2022]
Abstract
β-Adrenoceptor (β-AR)-mediated relaxation plays an important role in the regulation of vascular tone. β-AR-mediated vascular relaxation is reduced in various disease states and aging. We hypothesized that β-AR-mediated vasodilatation is impaired in DOCA-salt hypertension due to alterations in the cAMP pathway. β-AR-mediated relaxation was determined in small mesenteric arteries from DOCA-salt hypertensive and control uninephrectomized (Uni) rats. To exclude nitric oxide (NO) and cyclooxygenase (COX) pathways, relaxation responses were determined in the presence of l-NNA and indomethacin, NO synthase inhibitor and COX inhibitors, respectively. Isoprenaline (ISO)-induced relaxation was reduced in arteries from DOCA-salt compared to Uni rats. Protein kinase A (PKA) inhibitors (H89 or Rp-cAMPS) or adenylyl cyclase inhibitor (SQ22536) did not abolish the difference in ISO-induced relaxation between the groups. Forskolin (adenylyl cyclase activator)-induced relaxation was similar between the groups. The inhibition of IK(Ca)/SK(Ca) channels (TRAM-34 plus UCL1684) or BK(Ca) channels (iberiotoxin) reduced ISO-induced relaxation only in Uni rats and abolished the relaxation differences between the groups. The expression of SK(Ca) channel was decreased in DOCA-salt arteries. The expression of BK(Ca) channel α subunit was increased whereas the expression of BK(Ca) channel β subunit was decreased in DOCA-salt arteries. The expression of receptor for activated C kinase 1 (RACK1), which is a binding protein for BK(Ca) channel and negatively modulates its activity, was increased in DOCA-salt arteries. These results suggest that the impairment of β-AR-mediated relaxation in DOCA-salt mesenteric arteries may be attributable to altered IK(Ca)/SK(Ca) and/or BK(Ca) channels activities rather than cAMP/PKA pathway. Impaired β-AR-stimulated BK(Ca) channel activity may be due to the imbalance between its subunit expressions and RACK1 upregulation.
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Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
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Closure of multiple types of K+ channels is necessary to induce changes in renal vascular resistance in vivo in rats. Pflugers Arch 2011; 462:655-67. [DOI: 10.1007/s00424-011-1018-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 08/12/2011] [Accepted: 08/16/2011] [Indexed: 10/17/2022]
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Mechanisms involved in the nitric oxide-induced vasorelaxation in porcine prostatic small arteries. Naunyn Schmiedebergs Arch Pharmacol 2011; 384:245-53. [DOI: 10.1007/s00210-011-0666-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 06/26/2011] [Indexed: 10/18/2022]
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Mechanisms involved in the adenosine-induced vasorelaxation to the pig prostatic small arteries. Purinergic Signal 2011; 7:413-25. [PMID: 21567127 DOI: 10.1007/s11302-011-9238-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 05/04/2011] [Indexed: 10/18/2022] Open
Abstract
Benign prostatic hypertrophy has been related with glandular ischemia processes and adenosine is a potent vasodilator agent. This study investigates the mechanisms underlying the adenosine-induced vasorelaxation in pig prostatic small arteries. Adenosine receptors expression was determined by Western blot and immunohistochemistry, and rings were mounted in myographs for isometric force recording. A(2A) and A(3) receptor expression was observed in the arterial wall and A(2A)-immunoreactivity was identified in the adventitia-media junction and endothelium. A(1) and A(2B) receptor expression was not obtained. On noradrenaline-precontracted rings, P1 receptor agonists produced concentration-dependent relaxations with the following order of potency: 5'-N-ethylcarboxamidoadenosine (NECA) = CGS21680 > 2-Cl-IB-MECA = 2-Cl-cyclopentyladenosine = adenosine. Adenosine reuptake inhibition potentiated both NECA and adenosine relaxations. Endothelium removal and ZM241385, an A(2A) antagonist, reduced NECA relaxations that were not modified by A(1), A(2B), and A(3) receptor antagonists. Neuronal voltage-gated Ca(2+) channels and nitric oxide (NO) synthase blockade, and adenylyl cyclase activation enhanced these responses, which were reduced by protein kinase A inhibition and by blockade of the intermediate (IK(Ca))- and small (SK(Ca))-conductance Ca(2+)-activated K(+) channels. Inhibition of cyclooxygenase (COX), large-conductance Ca(2+)-activated-, ATP-dependent-, and voltage-gated-K(+) channel failed to modify these responses. These results suggest that adenosine induces endothelium-dependent relaxations in the pig prostatic arteries via A(2A) purinoceptors. The adenosine vasorelaxation, which is prejunctionally modulated, is produced via NO- and COX-independent mechanisms that involve activation of IK(Ca) and SK(Ca) channels and stimulation of adenylyl cyclase. Endothelium-derived NO playing a regulatory role under conditions in which EDHF is non-functional is also suggested. Adenosine-induced vasodilatation could be useful to prevent prostatic ischemia.
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Haddock RE, Grayson TH, Morris MJ, Howitt L, Chadha PS, Sandow SL. Diet-induced obesity impairs endothelium-derived hyperpolarization via altered potassium channel signaling mechanisms. PLoS One 2011; 6:e16423. [PMID: 21283658 PMCID: PMC3025034 DOI: 10.1371/journal.pone.0016423] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 12/15/2010] [Indexed: 11/20/2022] Open
Abstract
Background The vascular endothelium plays a critical role in the control of blood flow. Altered endothelium-mediated vasodilator and vasoconstrictor mechanisms underlie key aspects of cardiovascular disease, including those in obesity. Whilst the mechanism of nitric oxide (NO)-mediated vasodilation has been extensively studied in obesity, little is known about the impact of obesity on vasodilation to the endothelium-derived hyperpolarization (EDH) mechanism; which predominates in smaller resistance vessels and is characterized in this study. Methodology/Principal Findings Membrane potential, vessel diameter and luminal pressure were recorded in 4th order mesenteric arteries with pressure-induced myogenic tone, in control and diet-induced obese rats. Obesity, reflecting that of human dietary etiology, was induced with a cafeteria-style diet (∼30 kJ, fat) over 16–20 weeks. Age and sexed matched controls received standard chow (∼12 kJ, fat). Channel protein distribution, expression and vessel morphology were determined using immunohistochemistry, Western blotting and ultrastructural techniques. In control and obese rat vessels, acetylcholine-mediated EDH was abolished by small and intermediate conductance calcium-activated potassium channel (SKCa/IKCa) inhibition; with such activity being impaired in obesity. SKCa-IKCa activation with cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine (CyPPA) and 1-ethyl-2-benzimidazolinone (1-EBIO), respectively, hyperpolarized and relaxed vessels from control and obese rats. IKCa-mediated EDH contribution was increased in obesity, and associated with altered IKCa distribution and elevated expression. In contrast, the SKCa-dependent-EDH component was reduced in obesity. Inward-rectifying potassium channel (Kir) and Na+/K+-ATPase inhibition by barium/ouabain, respectively, attenuated and abolished EDH in arteries from control and obese rats, respectively; reflecting differential Kir expression and distribution. Although changes in medial properties occurred, obesity had no effect on myoendothelial gap junction density. Conclusion/Significance In obese rats, vasodilation to EDH is impaired due to changes in the underlying potassium channel signaling mechanisms. Whilst myoendothelial gap junction density is unchanged in arteries of obese compared to control, increased IKCa and Na+/K+-ATPase, and decreased Kir underlie changes in the EDH mechanism.
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Affiliation(s)
- Rebecca E. Haddock
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- Department of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail: (REH); (SLS)
| | - T. Hilton Grayson
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Margaret J. Morris
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Lauren Howitt
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Preet S. Chadha
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Shaun L. Sandow
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- * E-mail: (REH); (SLS)
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