1
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McCallinhart PE, Chade AR, Bender SB, Trask AJ. Expanding landscape of coronary microvascular disease in co-morbid conditions: Metabolic disease and beyond. J Mol Cell Cardiol 2024; 192:26-35. [PMID: 38734061 PMCID: PMC11340124 DOI: 10.1016/j.yjmcc.2024.05.004] [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: 03/01/2024] [Revised: 04/26/2024] [Accepted: 05/08/2024] [Indexed: 05/13/2024]
Abstract
Coronary microvascular disease (CMD) and impaired coronary blood flow control are defects that occur early in the pathogenesis of heart failure in cardiometabolic conditions, prior to the onset of atherosclerosis. In fact, recent studies have shown that CMD is an independent predictor of cardiac morbidity and mortality in patients with obesity and metabolic disease. CMD is comprised of functional, structural, and mechanical impairments that synergize and ultimately reduce coronary blood flow in metabolic disease and in other co-morbid conditions, including transplant, autoimmune disorders, chemotherapy-induced cardiotoxicity, and remote injury-induced CMD. This review summarizes the contemporary state-of-the-field related to CMD in metabolic and these other co-morbid conditions based on mechanistic data derived mostly from preclinical small- and large-animal models in light of available clinical evidence and given the limitations of studying these mechanisms in humans. In addition, we also discuss gaps in current understanding, emerging areas of interest, and opportunities for future investigations in this field.
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Affiliation(s)
- Patricia E McCallinhart
- Center for Cardiovascular Research, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States of America
| | - Alejandro R Chade
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, United States of America; Department of Medicine, University of Missouri School of Medicine, Columbia, MO, United States of America
| | - Shawn B Bender
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, United States of America; Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States of America; Research Service, Harry S Truman Memorial Veterans Hospital, Columbia, MO, United States of America.
| | - Aaron J Trask
- Center for Cardiovascular Research, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States of America; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, United States of America.
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2
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Feng L, Gao L. The role of neurovascular coupling dysfunction in cognitive decline of diabetes patients. Front Neurosci 2024; 18:1375908. [PMID: 38576869 PMCID: PMC10991808 DOI: 10.3389/fnins.2024.1375908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 03/05/2024] [Indexed: 04/06/2024] Open
Abstract
Neurovascular coupling (NVC) is an important mechanism to ensure adequate blood supply to active neurons in the brain. NVC damage can lead to chronic impairment of neuronal function. Diabetes is characterized by high blood sugar and is considered an important risk factor for cognitive impairment. In this review, we provide fMRI evidence of NVC damage in diabetic patients with cognitive decline. Combined with the exploration of the major mechanisms and signaling pathways of NVC, we discuss the effects of chronic hyperglycemia on the cellular structure of NVC signaling, including key receptors, ion channels, and intercellular connections. Studying these diabetes-related changes in cell structure will help us understand the underlying causes behind diabetes-induced NVC damage and early cognitive decline, ultimately helping to identify the most effective drug targets for treatment.
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Affiliation(s)
| | - Ling Gao
- Department of Endocrinology, Renmin Hospital of Wuhan University, Wuhan, China
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3
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Ca 2+-Sensitive Potassium Channels. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28020885. [PMID: 36677942 PMCID: PMC9861210 DOI: 10.3390/molecules28020885] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/07/2023] [Accepted: 01/10/2023] [Indexed: 01/18/2023]
Abstract
The Ca2+ ion is used ubiquitously as an intracellular signaling molecule due to its high external and low internal concentration. Many Ca2+-sensing ion channel proteins have evolved to receive and propagate Ca2+ signals. Among them are the Ca2+-activated potassium channels, a large family of potassium channels activated by rises in cytosolic calcium in response to Ca2+ influx via Ca2+-permeable channels that open during the action potential or Ca2+ release from the endoplasmic reticulum. The Ca2+ sensitivity of these channels allows internal Ca2+ to regulate the electrical activity of the cell membrane. Activating these potassium channels controls many physiological processes, from the firing properties of neurons to the control of transmitter release. This review will discuss what is understood about the Ca2+ sensitivity of the two best-studied groups of Ca2+-sensitive potassium channels: large-conductance Ca2+-activated K+ channels, KCa1.1, and small/intermediate-conductance Ca2+-activated K+ channels, KCa2.x/KCa3.1.
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4
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Gao S, Hua B, Liu Q, Liu H, Li W, Li H. Role of peroxisome proliferators-activated receptor-gamma in advanced glycation end product-mediated functional loss of voltage-gated potassium channel in rat coronary arteries. BMC Cardiovasc Disord 2020; 20:337. [PMID: 32664860 PMCID: PMC7362521 DOI: 10.1186/s12872-020-01613-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 07/06/2020] [Indexed: 11/23/2022] Open
Abstract
Background High blood glucose impairs voltage-gated K+ (Kv) channel-mediated vasodilation in rat coronary artery smooth muscle cells (CSMCs) via oxidative stress. Advanced glycation end product (AGE) and receptor for AGE (RAGE) axis has been found to impair coronary dilation by reducing Kv channel activity in diabetic rat small coronary arteries (RSCAs). However, its underlying mechanism remain unclear. Here, we used isolated arteries and primary CSMCs to investigate the effect of AGE incubation on Kv channel-mediated coronary dilation and the possible involvement of peroxisome proliferators-activated receptor (PPAR) -γ pathway. Methods The RSCAs and primary CSMCs were isolated, cultured, and treated with bovine serum albumin (BSA), AGE-BSA, alagrebrium (ALA, AGE cross-linking breaker), pioglitazone (PIO, PPAR-γ activator) and/or GW9662 (PPAR-γ inhibitor). The groups were accordingly divided as control, BSA, AGE, AGE + ALA, AGE + PIO, or AGE + PIO + GW9662. Kv channel-mediated dilation was analyzed using wire myograph. Histology and immunohistochemistry of RSCAs were performed. Western blot was used to detect the protein expression of RAGE, major Kv channel subunits expressed in CSMCs (Kv1.2 and Kv1.5), PPAR-γ, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-2 (NOX-2). Results AGE markedly reduced Forskolin-induced Kv channel-mediated dilation of RSCAs by engaging with RAGE, and ALA or PIO significantly reversed the functional loss of Kv channel. In both RSCAs and CSMCs, AGE reduced Kv1.2/1.5 expression, increased RAGE and NOX-2 expression, and inhibited PPAR-γ expression, while ALA or PIO treatment partially reversed the inhibiting effects of AGE on Kv1.2/1.5 expression, accompanied by the downregulation of RAGE and decreased oxidative stress. Meanwhile, silencing of RAGE with siRNA remarkably alleviated the AGE-induced downregulation of Kv1.2/1.5 expression in CSMCs. Conclusion AGE reduces the Kv channel expression in CSMCs and further impairs the Kv channel-mediated dilation in RSCAs. The AGE/RAGE axis may enhance oxidative stress by inhibiting the downstream PPAR-γ pathway, thus playing a critical role in the dysfunction of Kv channels.
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Affiliation(s)
- Side Gao
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng, Beijing, 100050, P. R. China
| | - Bing Hua
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng, Beijing, 100050, P. R. China
| | - Qingbo Liu
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng, Beijing, 100050, P. R. China
| | - Huirong Liu
- School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, P. R. China.,Beijing Key Laboratory of Metabolic Disorder Related Cardiovascular Disease, Beijing, 100069, P. R. China
| | - Weiping Li
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng, Beijing, 100050, P. R. China. .,Beijing Key Laboratory of Metabolic Disorder Related Cardiovascular Disease, Beijing, 100069, P. R. China.
| | - Hongwei Li
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng, Beijing, 100050, P. R. China. .,Beijing Key Laboratory of Metabolic Disorder Related Cardiovascular Disease, Beijing, 100069, P. R. China. .,Department of Internal Medicine, Medical Health Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, P. R. China.
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5
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Selvaraj C, Selvaraj G, Kaliamurthi S, Cho WC, Wei DQ, Singh SK. Ion Channels as Therapeutic Targets for Type 1 Diabetes Mellitus. Curr Drug Targets 2020; 21:132-147. [PMID: 31538892 DOI: 10.2174/1389450119666190920152249] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 02/07/2023]
Abstract
Ion channels are integral proteins expressed in almost all living cells and are involved in muscle contraction and nutrient transport. They play a critical role in the normal functioning of the excitable tissues of the nervous system and regulate the action potential and contraction events. Dysfunction of genes encodes ion channel proteins, which disrupt the channel function and lead to a number of diseases, among which is type 1 diabetes mellitus (T1DM). Therefore, understanding the complex mechanism of ion channel receptors is necessary to facilitate the diagnosis and management of treatment. In this review, we summarize the mechanism of important ion channels and their potential role in the regulation of insulin secretion along with the limitations of ion channels as therapeutic targets. Furthermore, we discuss the recent investigations of the mechanism regulating the ion channels in pancreatic beta cells, which suggest that ion channels are active participants in the regulation of insulin secretion.
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Affiliation(s)
- Chandrabose Selvaraj
- Department of Bioinformatics, Computer-Aided Drug Design, and Molecular Modeling Lab, Science Block, Alagappa University, Karaikudi, Tamil Nadu, 630004, India
| | - Gurudeeban Selvaraj
- Center of Interdisciplinary Sciences-Computational Life Sciences, College of Food Science and Engineering, Henan University of Technology, Zhengzhou, 450001, China
- Peng Cheng Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nanshan District, Shenzhen, Guangdong, 518055, China
| | - Satyavani Kaliamurthi
- Center of Interdisciplinary Sciences-Computational Life Sciences, College of Food Science and Engineering, Henan University of Technology, Zhengzhou, 450001, China
- Peng Cheng Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nanshan District, Shenzhen, Guangdong, 518055, China
| | - William C Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Kowloon, Hong Kong
| | - Dong-Qing Wei
- Center of Interdisciplinary Sciences-Computational Life Sciences, College of Food Science and Engineering, Henan University of Technology, Zhengzhou, 450001, China
- Peng Cheng Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nanshan District, Shenzhen, Guangdong, 518055, China
- Department of Bioinformatics, The State Key Laboratory of Microbial Metabolism, College of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Sanjeev Kumar Singh
- Department of Bioinformatics, Computer-Aided Drug Design, and Molecular Modeling Lab, Science Block, Alagappa University, Karaikudi, Tamil Nadu, 630004, India
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6
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Inhibition of the Voltage-Dependent K + Current by the Tricyclic Antidepressant Desipramine in Rabbit Coronary Arterial Smooth Muscle Cells. Cardiovasc Toxicol 2019; 18:252-260. [PMID: 29134326 DOI: 10.1007/s12012-017-9435-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We describe the effect of a tricyclic antidepressant drug desipramine on voltage-dependent K+ (Kv) currents in freshly isolated rabbit coronary arterial smooth muscle cells using a conventional whole-cell patch clamp technique. Application of desipramine rapidly decreased the Kv current amplitude in a concentration-dependent manner, with an IC50 value of 5.91 ± 0.18 μM and a Hill coefficient of 0.61 ± 0.09. The steady-state inactivation curves of the Kv channels were not affected by desipramine. However, desipramine shifted the steady-state inactivation curves toward a more negative potential. Application of train pulses (1 or 2 Hz) slightly reduced the Kv current amplitude. Such reduction in the Kv current amplitude by train pulses increased in the presence of desipramine. Furthermore, the inactivation recovery time constant was also increased in the presence of desipramine, suggesting that desipramine-induced inhibition of the Kv current was use-dependent. Application of a Kv1.5 inhibitor (DPO-1) and/or a Kv2.1 inhibitor (guangxitoxin) did not change the inhibitory effect of desipramine on Kv currents. Based on these results, we concluded that desipramine directly inhibited the Kv channels in a dose- and state-dependent manner, but the effect was independent of norepinephrine/serotonin reuptake inhibition.
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7
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Dopico AM, Bukiya AN, Jaggar JH. Calcium- and voltage-gated BK channels in vascular smooth muscle. Pflugers Arch 2018; 470:1271-1289. [PMID: 29748711 DOI: 10.1007/s00424-018-2151-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 04/27/2018] [Indexed: 02/04/2023]
Abstract
Ion channels in vascular smooth muscle regulate myogenic tone and vessel contractility. In particular, activation of calcium- and voltage-gated potassium channels of large conductance (BK channels) results in outward current that shifts the membrane potential toward more negative values, triggering a negative feed-back loop on depolarization-induced calcium influx and SM contraction. In this short review, we first present the molecular basis of vascular smooth muscle BK channels and the role of subunit composition and trafficking in the regulation of myogenic tone and vascular contractility. BK channel modulation by endogenous signaling molecules, and paracrine and endocrine mediators follows. Lastly, we describe the functional changes in smooth muscle BK channels that contribute to, or are triggered by, common physiological conditions and pathologies, including obesity, diabetes, and systemic hypertension.
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Affiliation(s)
- Alex M Dopico
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St., Memphis, TN, 38163, USA.
| | - Anna N Bukiya
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St., Memphis, TN, 38163, USA
| | - Jonathan H Jaggar
- Department of Physiology, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, USA
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8
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Kibel A, Selthofer-Relatic K, Drenjancevic I, Bacun T, Bosnjak I, Kibel D, Gros M. Coronary microvascular dysfunction in diabetes mellitus. J Int Med Res 2017; 45:1901-1929. [PMID: 28643578 PMCID: PMC5805190 DOI: 10.1177/0300060516675504] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 09/30/2016] [Indexed: 12/16/2022] Open
Abstract
The significance, mechanisms and consequences of coronary microvascular dysfunction associated with diabetes mellitus are topics into which we have insufficient insight at this time. It is widely recognized that endothelial dysfunction that is caused by diabetes in various vascular beds contributes to a wide range of complications and exerts unfavorable effects on microcirculatory regulation. The coronary microcirculation is precisely regulated through a number of interconnected physiological processes with the purpose of matching local blood flow to myocardial metabolic demands. Dysregulation of this network might contribute to varying degrees of pathological consequences. This review discusses the most important findings regarding coronary microvascular dysfunction in diabetes from pre-clinical and clinical perspectives.
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Affiliation(s)
- Aleksandar Kibel
- Department for Heart and Vascular
Diseases, Clinic of Internal Medicine, Osijek University Hospital, Osijek,
Croatia
- Department of Physiology and Immunology,
Faculty of Medicine, University of Osijek, Croatia
| | - Kristina Selthofer-Relatic
- Department for Heart and Vascular
Diseases, Clinic of Internal Medicine, Osijek University Hospital, Osijek,
Croatia
- Department of Internal Medicine, Faculty
of Medicine, University of Osijek, Osijek, Croatia
| | - Ines Drenjancevic
- Department of Physiology and Immunology,
Faculty of Medicine, University of Osijek, Croatia
| | - Tatjana Bacun
- Department of Internal Medicine, Faculty
of Medicine, University of Osijek, Osijek, Croatia
- Department of Endocrinology, Clinic of
Internal Medicine, Osijek University Hospital, Osijek, Croatia
| | - Ivica Bosnjak
- Department for Heart and Vascular
Diseases, Clinic of Internal Medicine, Osijek University Hospital, Osijek,
Croatia
| | - Dijana Kibel
- Department of Physiology and Immunology,
Faculty of Medicine, University of Osijek, Croatia
- Department of Diagnostic and
Interventional Radiology, Osijek University Hospital, Osijek, Croatia
| | - Mario Gros
- Department of Physiology and Immunology,
Faculty of Medicine, University of Osijek, Croatia
- Department of Diagnostic and
Interventional Radiology, Osijek University Hospital, Osijek, Croatia
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9
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Hong DH, Li H, Kim HW, Kim HS, Son YK, Yang SR, Park JR, Ha KS, Han ET, Hong SH, Firth AL, Na SH, Park WS. Alterations of voltage-dependent K(+) channels in the mesenteric artery during the early and chronic phases of diabetes. Clin Exp Pharmacol Physiol 2017; 43:808-17. [PMID: 27218229 DOI: 10.1111/1440-1681.12599] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 05/12/2016] [Accepted: 05/20/2016] [Indexed: 12/26/2022]
Abstract
This study investigated the alteration of voltage-dependent K(+) (Kv) channels in mesenteric arterial smooth muscle cells from control (Long-Evans Tokushima Otsuka [LETO]) and diabetic (Otsuka Long-Evans Tokushima Fatty [OLETF]) rats during the early and chronic phases of diabetes. We demonstrated alterations in the mesenteric Kv channels during the early and chronic phase of diabetes using the patch-clamp technique, the arterial tone measurement system, and RT-PCR in Long-Evans Tokushima (LETO; for control) and Otsuka Long-Evans Tokushima Fatty (OLETF; for diabetes) type 2 diabetic model rats. In the early phase of diabetes, the amplitude of mesenteric Kv currents induced by depolarizing pulses was greater in OLETF rats than in LETO rats. The contractile response of the mesenteric artery induced by the Kv inhibitor, 4-aminopyridine (4-AP), was also greater in OLETF rats. The expression of most Kv subtypes- including Kv1.1, Kv1.2, Kv1.4, Kv1.5, Kv1.6, Kv2.1, Kv3.2, Kv4.1, Kv4.3, Kv5.1, Kv6.2, Kv8.1, Kv9.3, and Kv10.1-were increased in mesenteric arterial smooth muscle from OLETF rats compared with LETO rats. However, in the chronic phase of diabetes, the Kv current amplitude did not differ between LETO and OLETF rats. In addition, the 4-AP-induced contractile response of the mesenteric artery and the expression of Kv subtypes did not differ between the two groups. The increased Kv current amplitude and Kv channel-related contractile response were attributable to the increase in Kv channel expression during the early phase of diabetes. The increased Kv current amplitude and Kv channel-related contractile response were reversed during the chronic phase of diabetes.
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Affiliation(s)
- Da Hye Hong
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Hongliang Li
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Hye Won Kim
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Han Sol Kim
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Youn Kyoung Son
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Se-Ran Yang
- Department of Thoracic and Cardiovascular Surgery, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Jeong-Ran Park
- Department of Thoracic and Cardiovascular Surgery, Kangwon National University School of Medicine, Chuncheon, South Korea.,Institute of Medical Sciences, Kangwon National University, Chuncheon, South Korea
| | - Kwon-Soo Ha
- Department of Molecular and Cellular Biochemistry, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Seok-Ho Hong
- Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Amy L Firth
- Department of Pulmonary, Critical Care and Sleep Medicine, University of Southern California, Keck School of Medicine, Los Angeles, CA, USA
| | - Sung Hun Na
- Institute of Medical Sciences, Department of Obstetrics and Gynecology, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Won Sun Park
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
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10
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Ewart MA, Ugusman A, Vishwanath A, Almabrouk TA, Alganga H, Katwan OJ, Hubanova P, Currie S, Kennedy S. Changes in IP3 Receptor Expression and Function in Aortic Smooth Muscle of Atherosclerotic Mice. J Vasc Res 2017; 54:68-78. [PMID: 28365690 PMCID: PMC5804831 DOI: 10.1159/000461581] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 02/09/2017] [Indexed: 01/01/2023] Open
Abstract
Peroxynitrite is an endothelium-independent vasodilator that induces relaxation via membrane hyperpolarization. The activation of IP3 receptors triggers the opening of potassium channels and hyperpolarization. Previously we found that relaxation to peroxynitrite was maintained during the development of atherosclerosis due to changes in the expression of calcium-regulatory proteins. In this study we investigated: (1) the mechanism of peroxynitrite-induced relaxation in the mouse aorta, (2) the effect of atherosclerosis on relaxation to peroxynitrite and other vasodilators, and (3) the effect of atherosclerosis on the expression and function of the IP3 receptor. Aortic function was studied using wire myography, and atherosclerosis was induced by fat-feeding ApoE−/− mice. The expression of IP3 receptors was studied using Western blotting and immunohistochemistry. Relaxation to peroxynitrite was attenuated by the IP3 antagonists 2-APB and xestospongin C and also the Kv channel blocker 4-aminopyridine (4-AP). Atherosclerosis attenuated vasodilation to cromakalim and the AMPK activator A769662 but not peroxynitrite. Relaxation was attenuated to a greater extent by 2-APB in atherosclerotic aortae despite the reduced expression of IP3 receptors. 4-AP was less effective in ApoE−/− mice fat-fed for 4 months. Peroxynitrite relaxation involves an IP3-induced calcium release and KV channel activation. This mechanism becomes less important as atherosclerosis develops, and relaxation to peroxynitrite may be maintained by increased calcium extrusion.
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MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Aorta, Thoracic/physiopathology
- Aortic Diseases/genetics
- Aortic Diseases/metabolism
- Aortic Diseases/physiopathology
- Apolipoproteins E/deficiency
- Apolipoproteins E/genetics
- Atherosclerosis/genetics
- Atherosclerosis/metabolism
- Atherosclerosis/physiopathology
- Calcium Signaling
- Diet, High-Fat
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Genetic Predisposition to Disease
- Inositol 1,4,5-Trisphosphate Receptors/agonists
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Peroxynitrous Acid/pharmacology
- Phenotype
- Potassium Channels, Voltage-Gated/metabolism
- Vasodilation/drug effects
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Marie-Ann Ewart
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Azizah Ugusman
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Department of Physiology, Faculty of Medicine, National University of Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Anisha Vishwanath
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Tarek A.M. Almabrouk
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Husam Alganga
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Omar J. Katwan
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Pavlina Hubanova
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Susan Currie
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, UK
| | - Simon Kennedy
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- *Dr. Simon Kennedy, Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ (UK), E-Mail
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11
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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Calycosin and Formononetin Induce Endothelium-Dependent Vasodilation by the Activation of Large-Conductance Ca 2+-Activated K + Channels (BK Ca). EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:5272531. [PMID: 27994632 PMCID: PMC5141325 DOI: 10.1155/2016/5272531] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/26/2016] [Accepted: 10/19/2016] [Indexed: 12/13/2022]
Abstract
Calycosin and formononetin are two structurally similar isoflavonoids that have been shown to induce vasodilation in aorta and conduit arteries, but study of their actions on endothelial functions is lacking. Here, we demonstrated that both isoflavonoids relaxed rat mesenteric resistance arteries in a concentration-dependent manner, which was reduced by endothelial disruption and nitric oxide synthase (NOS) inhibition, indicating the involvement of both endothelium and vascular smooth muscle. In addition, the endothelium-dependent vasodilation, but not the endothelium-independent vasodilation, was blocked by BKCa inhibitor iberiotoxin (IbTX). Using human umbilical vein endothelial cells (HUVECs) as a model, we showed calycosin and formononetin induced dose-dependent outwardly rectifying K+ currents using whole cell patch clamp. These currents were blocked by tetraethylammonium chloride (TEACl), charybdotoxin (ChTX), or IbTX, but not apamin. We further demonstrated that both isoflavonoids significantly increased nitric oxide (NO) production and upregulated the activities and expressions of endothelial NOS (eNOS) and neuronal NOS (nNOS). These results suggested that calycosin and formononetin act as endothelial BKCa activators for mediating endothelium-dependent vasodilation through enhancing endothelium hyperpolarization and NO production. Since activation of BKCa plays a role in improving behavioral and cognitive disorders, we suggested that these two isoflavonoids could provide beneficial effects to cognitive disorders through vascular regulation.
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Jarrett CL, Ahmed Z, Faust JJ, Sweazea KL. High glucose impairs acetylcholine-mediated vasodilation in isolated arteries from Mourning doves (Z. macroura). Comp Biochem Physiol A Mol Integr Physiol 2016; 201:141-145. [DOI: 10.1016/j.cbpa.2016.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 07/07/2016] [Accepted: 07/10/2016] [Indexed: 11/28/2022]
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Cheng XQ, Zhang JY, Gao SS, Wu H, Zuo YM, Gu EW, Chen ZW. Sufentanil attenuates impairment of the endothelium-dependent vasodilation induced by hypoxia-reoxygenation in the rat coronary artery. Can J Physiol Pharmacol 2016; 94:1309-1314. [PMID: 27533316 DOI: 10.1139/cjpp-2016-0037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sufentanil has been used broadly in cardiac surgery, but the mechanisms by which it modulates coronary vascular tone after ischemia-reperfusion injury are largely unknown. Effects of sufentanil on coronary tone and on the relaxation of rat coronary arteries (CAs) in response to endothelium-dependent (acetylcholine) and endothelium-independent (sodium nitroprusside) relaxing agents in the presence of hypoxia-reoxygenation (H/R) was studied in an in vitro organ chamber setup. Sufentanil (10-7-10-4 mol/L) relaxed rat CA rings in endothelium-dependent and endothelium-independent manners. In endothelium-intact rings, preincubation of H/R-treated CAs with sufentanil (10-5 mol/L) significantly increased the acetylcholine response, but did not augment sodium nitroprusside-induced relaxation. Sufentanil-mediated potentiation of acetylcholine-induced relaxation was not affected by a nitric oxide synthase inhibitor or by intermediate- or small-conductance Ca2+-activated K+ channel blockers. However, potentiation was abolished by iberiotoxin (100 nmol/L), a selective inhibitor of large-conductance Ca2+-activated K+ channels, as well as Rp-cAMPS (30 μmol/L), a cyclic AMP-dependent protein kinase (PKA) inhibitor. Sufentanil induced endothelium-dependent and endothelium-independent relaxation and attenuated H/R-induced impairment of endothelium-dependent vasodilation in the rat CAs. The potentiating effect of sufentanil may involve activation of large-conductance Ca2+-activated K+ channels via cAMP-dependent mechanisms.
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Affiliation(s)
- Xin-Qi Cheng
- a Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, Anhui, China.,b Department of Anaesthesiology, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China
| | - Jun-Yan Zhang
- a Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, Anhui, China
| | - Shan-Shan Gao
- a Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, Anhui, China
| | - Hao Wu
- b Department of Anaesthesiology, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China
| | - You-Mei Zuo
- b Department of Anaesthesiology, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China
| | - Er-Wei Gu
- b Department of Anaesthesiology, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China
| | - Zhi-Wu Chen
- a Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, Anhui, China
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15
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Potassium Channels in Regulation of Vascular Smooth Muscle Contraction and Growth. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:89-144. [PMID: 28212804 DOI: 10.1016/bs.apha.2016.07.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Potassium channels importantly contribute to the regulation of vascular smooth muscle (VSM) contraction and growth. They are the dominant ion conductance of the VSM cell membrane and importantly determine and regulate membrane potential. Membrane potential, in turn, regulates the open-state probability of voltage-gated Ca2+ channels (VGCC), Ca2+ influx through VGCC, intracellular Ca2+, and VSM contraction. Membrane potential also affects release of Ca2+ from internal stores and the Ca2+ sensitivity of the contractile machinery such that K+ channels participate in all aspects of regulation of VSM contraction. Potassium channels also regulate proliferation of VSM cells through membrane potential-dependent and membrane potential-independent mechanisms. VSM cells express multiple isoforms of at least five classes of K+ channels that contribute to the regulation of contraction and cell proliferation (growth). This review will examine the structure, expression, and function of large conductance, Ca2+-activated K+ (BKCa) channels, intermediate-conductance Ca2+-activated K+ (KCa3.1) channels, multiple isoforms of voltage-gated K+ (KV) channels, ATP-sensitive K+ (KATP) channels, and inward-rectifier K+ (KIR) channels in both contractile and proliferating VSM cells.
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16
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Gutterman DD, Chabowski DS, Kadlec AO, Durand MJ, Freed JK, Ait-Aissa K, Beyer AM. The Human Microcirculation: Regulation of Flow and Beyond. Circ Res 2016; 118:157-72. [PMID: 26837746 DOI: 10.1161/circresaha.115.305364] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The microcirculation is responsible for orchestrating adjustments in vascular tone to match local tissue perfusion with oxygen demand. Beyond this metabolic dilation, the microvasculature plays a critical role in modulating vascular tone by endothelial release of an unusually diverse family of compounds including nitric oxide, other reactive oxygen species, and arachidonic acid metabolites. Animal models have provided excellent insight into mechanisms of vasoregulation in health and disease. However, there are unique aspects of the human microcirculation that serve as the focus of this review. The concept is put forth that vasculoparenchymal communication is multimodal, with vascular release of nitric oxide eliciting dilation and preserving normal parenchymal function by inhibiting inflammation and proliferation. Likewise, in disease or stress, endothelial release of reactive oxygen species mediates both dilation and parenchymal inflammation leading to cellular dysfunction, thrombosis, and fibrosis. Some pathways responsible for this stress-induced shift in mediator of vasodilation are proposed. This paradigm may help explain why microvascular dysfunction is such a powerful predictor of cardiovascular events and help identify new approaches to treatment and prevention.
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Affiliation(s)
- David D Gutterman
- From the Cardiovascular Center (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A., M.J.D.), Departments of Medicine (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A.), Pharmacology and Toxicology (D.S.C., J.K.F.), Physiology (A.M.B., A.O.K.), Physical Medicine and Rehabilitation (M.J.D.), and Anesthesiology (J.K.F.), Medical College of Wisconsin, Milwaukee.
| | - Dawid S Chabowski
- From the Cardiovascular Center (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A., M.J.D.), Departments of Medicine (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A.), Pharmacology and Toxicology (D.S.C., J.K.F.), Physiology (A.M.B., A.O.K.), Physical Medicine and Rehabilitation (M.J.D.), and Anesthesiology (J.K.F.), Medical College of Wisconsin, Milwaukee
| | - Andrew O Kadlec
- From the Cardiovascular Center (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A., M.J.D.), Departments of Medicine (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A.), Pharmacology and Toxicology (D.S.C., J.K.F.), Physiology (A.M.B., A.O.K.), Physical Medicine and Rehabilitation (M.J.D.), and Anesthesiology (J.K.F.), Medical College of Wisconsin, Milwaukee
| | - Matthew J Durand
- From the Cardiovascular Center (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A., M.J.D.), Departments of Medicine (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A.), Pharmacology and Toxicology (D.S.C., J.K.F.), Physiology (A.M.B., A.O.K.), Physical Medicine and Rehabilitation (M.J.D.), and Anesthesiology (J.K.F.), Medical College of Wisconsin, Milwaukee
| | - Julie K Freed
- From the Cardiovascular Center (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A., M.J.D.), Departments of Medicine (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A.), Pharmacology and Toxicology (D.S.C., J.K.F.), Physiology (A.M.B., A.O.K.), Physical Medicine and Rehabilitation (M.J.D.), and Anesthesiology (J.K.F.), Medical College of Wisconsin, Milwaukee
| | - Karima Ait-Aissa
- From the Cardiovascular Center (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A., M.J.D.), Departments of Medicine (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A.), Pharmacology and Toxicology (D.S.C., J.K.F.), Physiology (A.M.B., A.O.K.), Physical Medicine and Rehabilitation (M.J.D.), and Anesthesiology (J.K.F.), Medical College of Wisconsin, Milwaukee
| | - Andreas M Beyer
- From the Cardiovascular Center (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A., M.J.D.), Departments of Medicine (A.M.B., A.O.K., D.D.G., D.S.C., J.K.F., K.A.-A.), Pharmacology and Toxicology (D.S.C., J.K.F.), Physiology (A.M.B., A.O.K.), Physical Medicine and Rehabilitation (M.J.D.), and Anesthesiology (J.K.F.), Medical College of Wisconsin, Milwaukee
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Krishnamoorthy-Natarajan G, Koide M. BK Channels in the Vascular System. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 128:401-38. [PMID: 27238270 DOI: 10.1016/bs.irn.2016.03.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Autoregulation of blood flow is essential for the preservation of organ function to ensure continuous supply of oxygen and essential nutrients and removal of metabolic waste. This is achieved by controlling the diameter of muscular arteries and arterioles that exhibit a myogenic response to changes in arterial blood pressure, nerve activity and tissue metabolism. Large-conductance voltage and Ca(2+)-dependent K(+) channels (BK channels), expressed exclusively in smooth muscle cells (SMCs) in the vascular wall of healthy arteries, play a critical role in regulating the myogenic response. Activation of BK channels by intracellular, local, and transient ryanodine receptor-mediated "Ca(2+) sparks," provides a hyperpolarizing influence on the SMC membrane potential thereby decreasing the activity of voltage-dependent Ca(2+) channels and limiting Ca(2+) influx to promote SMC relaxation and vasodilation. The BK channel α subunit, a large tetrameric protein with each monomer consisting of seven-transmembrane domains, a long intracellular C-terminal tail and an extracellular N-terminus, associates with the β1 and γ subunits in vascular SMCs. The BK channel is regulated by factors originating within the SMC or from the endothelium, perivascular nerves and circulating blood, that significantly alter channel gating properties, Ca(2+) sensitivity and expression of the α and/or β1 subunit. The BK channel thus serves as a central receiving dock that relays the effects of the changes in several such concomitant autocrine and paracrine factors and influences cardiovascular health. This chapter describes the primary mechanism of regulation of myogenic response by BK channels and the alterations to this mechanism wrought by different vasoactive mediators.
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Affiliation(s)
| | - M Koide
- University of Vermont, Burlington, VT, United States
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18
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Differential regulation of TRPV1 channels by H2O2: implications for diabetic microvascular dysfunction. Basic Res Cardiol 2016; 111:21. [PMID: 26907473 DOI: 10.1007/s00395-016-0539-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 02/11/2016] [Indexed: 12/21/2022]
Abstract
We demonstrated previously that TRPV1-dependent coupling of coronary blood flow (CBF) to metabolism is disrupted in diabetes. A critical amount of H2O2 contributes to CBF regulation; however, excessive H2O2 impairs responses. We sought to determine the extent to which differential regulation of TRPV1 by H2O2 modulates CBF and vascular reactivity in diabetes. We used contrast echocardiography to study TRPV1 knockout (V1KO), db/db diabetic, and wild type C57BKS/J (WT) mice. H2O2 dose-dependently increased CBF in WT mice, a response blocked by the TRPV1 antagonist SB366791. H2O2-induced vasodilation was significantly inhibited in db/db and V1KO mice. H2O2 caused robust SB366791-sensitive dilation in WT coronary microvessels; however, this response was attenuated in vessels from db/db and V1KO mice, suggesting H2O2-induced vasodilation occurs, in part, via TRPV1. Acute H2O2 exposure potentiated capsaicin-induced CBF responses and capsaicin-mediated vasodilation in WT mice, whereas prolonged luminal H2O2 exposure blunted capsaicin-induced vasodilation. Electrophysiology studies re-confirms acute H2O2 exposure activated TRPV1 in HEK293A and bovine aortic endothelial cells while establishing that H2O2 potentiate capsaicin-activated TRPV1 currents, whereas prolonged H2O2 exposure attenuated TRPV1 currents. Verification of H2O2-mediated activation of intrinsic TRPV1 specific currents were found in isolated mouse coronary endothelial cells from WT mice and decreased in endothelial cells from V1KO mice. These data suggest prolonged H2O2 exposure impairs TRPV1-dependent coronary vascular signaling. This may contribute to microvascular dysfunction and tissue perfusion deficits characteristic of diabetes.
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Hydrogen peroxide induces vasorelaxation by enhancing 4-aminopyridine-sensitive Kv currents through S-glutathionylation. Pflugers Arch 2014; 467:285-97. [PMID: 24756196 PMCID: PMC4293500 DOI: 10.1007/s00424-014-1513-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/04/2014] [Accepted: 04/02/2014] [Indexed: 12/04/2022]
Abstract
Hydrogen peroxide (H2O2) is an endothelium-derived hyperpolarizing factor. Since opposing vasoactive effects have been reported for H2O2 depending on the vascular bed and experimental conditions, this study was performed to assess whether H2O2 acts as a vasodilator in the rat mesenteric artery and, if so, to determine the underlying mechanisms. H2O2 elicited concentration-dependent relaxation in mesenteric arteries precontracted with norepinephrine. The vasodilatory effect of H2O2 was reversed by treatment with dithiothreitol. H2O2-elicited vasodilation was significantly reduced by blocking 4-aminopyridine (4-AP)-sensitive Kv channels, but it was resistant to blockers of big-conductance Ca2+-activated K+ channels and inward rectifier K+ channels. A patch-clamp study in mesenteric arterial smooth muscle cells (MASMCs) showed that H2O2 increased Kv currents in a concentration-dependent manner. H2O2 speeded up Kv channel activation and shifted steady state activation to hyperpolarizing potentials. Similar channel activation was seen with oxidized glutathione (GSSG). The H2O2-mediated channel activation was prevented by glutathione reductase. Consistent with S-glutathionylation, streptavidin pull-down assays with biotinylated glutathione ethyl ester showed incorporation of glutathione (GSH) in the Kv channel proteins in the presence of H2O2. Interestingly, conditions of increased oxidative stress within MASMCs impaired the capacity of H2O2 to stimulate Kv channels. Not only was the H2O2 stimulatory effect much weaker, but the inhibitory effect of H2O2 was unmasked. These data suggest that H2O2 activates 4-AP-sensitive Kv channels, possibly through S-glutathionylation, which elicits smooth muscle relaxation in rat mesenteric arteries. Furthermore, our results support the idea that the basal redox status of MASMCs determines the response of Kv currents to H2O2.
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Abstract
More than half of all patients with diabetes develop neuropathic disorders affecting the distal sensory and/or motor nerves, or autonomic or cranial nerve functions. Glycemic control can decrease the incidence of neuropathy but is not adequate alone to prevent or treat the disease. This chapter introduces diabetic neuropathy with a morphological description of the disease then describes our current understanding of metabolic and molecular mechanisms that contribute to neurovascular dysfunctions. Key mechanisms include glucose and lipid imbalances and insulin resistance that are interconnected via oxidative stress, inflammation, and altered gene expression. These complex interactions should be considered for the development of new treatment strategies against the onset or progression of neuropathy. Advances in understanding the combined metabolic stressors and the novel study of epigenetics suggest new therapeutic targets to combat this morbid and intractable disease affecting millions of patients with type 1 or type 2 diabetes.
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21
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Acute exposure of methylglyoxal leads to activation of KATP channels expressed in HEK293 cells. Acta Pharmacol Sin 2014; 35:58-64. [PMID: 24122011 DOI: 10.1038/aps.2013.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 07/21/2013] [Indexed: 12/16/2022] Open
Abstract
AIM Highly reactive carbonyl methylglyoxal (MGO) is one of the metabolites excessively produced in diabetes. We have showed that prolonged exposure of vascular smooth muscle cells to MGO leads to instability of the mRNA encoding ATP-sensitive potassium (KATP) channel. In the present study we investigated the effects of MGO on the activity of KATP channels. METHODS Kir6.1/ SUR2B, Kir6.2/SUR2B or Kir6.2Δ36 (a truncated Kir6.2 isoform) alone was expressed in HEK293 cells. Whole-cell currents were recorded in the cells with an Axopatch 200B amplifier. Macroscopic currents and single-channel currents were recorded in giant inside-out patches and normal inside-out patches, respectively. Data were analyzed using Clampfit 9 software. RESULTS The basal activity of Kir6.1/SUR2B channels was low. The specific KATP channel opener pinacidil (10 μmol/L) could fully activate Kir6.1/SUR2B channels, which was inhibited by the specific KATP channel blocker glibenclamide (10 μmol/L). MGO (0.1-10 mmol/L) dose-dependently activated Kir6.1/SUR2B channels with an EC50 of 1.7 mmol/L. The activation of Kir6.1/SUR2B channels by MGO was reversible upon washout, and could be inhibited completely by glibenclamide. Kir6.2Δ36 channels expressed in HEK293 cells could open automatically, and the channel activity was enhanced in the presence of MGO (3 mmol/L). Single channel recordings showed that MGO (3 mmol/L) markedly increased the open probability of Kir6.1/SUR2B channels, leaving the channel conductance unaltered. CONCLUSION Acute application of MGO activates KATP channels through direct, non-covalent and reversible interactions with the Kir6 subunits.
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22
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Nevelsteen I, Van den Bergh A, Van der Mieren G, Vanderper A, Mubagwa K, Bult H, Herijgers P. NO-dependent endothelial dysfunction in type II diabetes is aggravated by dyslipidemia and hypertension, but can be restored by angiotensin-converting enzyme inhibition and weight loss. J Vasc Res 2013; 50:486-97. [PMID: 24192582 DOI: 10.1159/000355221] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 08/19/2013] [Indexed: 11/19/2022] Open
Abstract
AIMS Insulin resistance, dyslipidemia and hypertension are independent mediators of endothelial dysfunction. It is incompletely defined whether dyslipidemia and hypertension in addition to diabetes mellitus type II (DMII), as seen in the metabolic syndrome (MS), worsen diabetes-induced endothelial dysfunction. Furthermore, it is unclear whether treatment influences endothelial dysfunction similarly in MS and DMII. Therefore, we studied vascular reactivity and the effect of in vivo treatment with angiotensin-converting enzyme inhibition (ACE-I) or hypocaloric diet in LDL receptor- and leptin-deficient (ob/ob), double knockout mice (DKO), featuring MS and in ob/ob mice with DMII. METHODS AND RESULTS Vascular reactivity was studied in isolated aortic ring segments. Maximum vasorelaxant response to acetylcholine (Ach) was more depressed in DKO than in ob/ob mice, whereas response to bradykinin (BK) was equally attenuated in both genotypes (52 ± 3 and 23 ± 9% reversal of preconstriction induced by 10(-7) M phenylephrine in DKO vs. 76 ± 3 and 23 ± 8% reversal of preconstriction in ob/ob mice, respectively). ACE-I and hypocaloric diet improved ACh-induced vasorelaxation significantly (89 ± 2 and 59 ± 2% reversal of preconstriction in DKO vs. 80 ± 3 and 84 ± 4% in ob/ob mice, respectively), but not the response to BK. CONCLUSION These results indicate a differential impact of DMII and MS on endothelial function. ACE-I and hypocaloric diet improved ACh-, but not BK-induced vasorelaxation in these mouse models of DMII and MS.
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Affiliation(s)
- Ines Nevelsteen
- Department of Cardiovascular Sciences, Research Unit of Experimental Cardiac Surgery, KU Leuven, Leuven, Belgium
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Abstract
The endothelium plays a critical role in the maintenance of cardiovascular health by producing nitric oxide and other vasoactive materials. Aging is associated with a gradual decline in this functional aspect of endothelial regulation of cardiovascular homeostasis. Indeed, age is an independent risk factor for cardiovascular diseases and is in part an important factor in the increased exponential mortality rates from vascular disease such as myocardial infarction and stroke that occurs in the ageing population. There are a number of mechanisms suggested to explain age-related endothelial dysfunction. However, recent scientific studies have advanced the notion of oxidative stress and inflammation as the two major risk factors underlying aging and age-related diseases. Regular physical activity, known to have a favorable effect on cardiovascular health, can also improve the function of the ageing endothelium by modulating oxidative stress and inflammatory processes, as we discuss in this paper.
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Affiliation(s)
- Saeid Golbidi
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Ismail Laher
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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Yang Y, Li S, Konduru AS, Zhang S, Trower TC, Shi W, Cui N, Yu L, Wang Y, Zhu D, Jiang C. Prolonged exposure to methylglyoxal causes disruption of vascular KATP channel by mRNA instability. Am J Physiol Cell Physiol 2012; 303:C1045-54. [PMID: 22972803 DOI: 10.1152/ajpcell.00020.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diabetes mellitus is characterized by hyperglycemia and excessive production of intermediary metabolites including methylglyoxal (MGO), a reactive carbonyl species that can lead to cell injuries. Interacting with proteins, lipids, and DNA, excessive MGO can cause dysfunction of various tissues, especially the vascular walls where diabetic complications often take place. However, the potential vascular targets of excessive MGO remain to be fully understood. Here we show that the vascular Kir6.1/SUR2B isoform of ATP-sensitive K(+) (K(ATP)) channels is likely to be disrupted with an exposure to submillimolar MGO. Up to 90% of the Kir6.1/SUR2B currents were suppressed by 1 mM MGO with a time constant of ∼2 h. Consistently, MGO treatment caused a vast reduction of both Kir6.1 and SUR2B mRNAs endogenously expressed in the A10 vascular smooth muscle cells. In the presence of the transcriptional inhibitor actinomycin-D, MGO remained to lower the Kir6.1 and SUR2B mRNAs to the same degree as MGO alone, suggesting that the MGO effect is likely to compromise the mRNA stability. Luciferase reporter assays indicated that the 3'-untranslated regions (UTRs) of the Kir6.1 but not SUR2 mRNA were targeted by MGO. In contrast, the SUR2B mRNAs obtained with in vitro transcription were disrupted by MGO directly, while the Kir6.1 transcripts were unaffected. Consistent with these results, the constriction of mesenteric arterial rings was markedly augmented with an exposure to 1 mM MGO for 2 h, and such an MGO effect was totally eliminated in the presence of glibenclamide. These results therefore suggest that acting on the 3'-UTR of Kir6.1 and the coding region of SUR2B, MGO causes instability of Kir6.1 and SUR2B mRNAs, disruption of vascular K(ATP) channels, and impairment of arterial function.
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Affiliation(s)
- Yang Yang
- Deptartment of Biology, Georgia State University, 100 Piedmont Ave., Atlanta, GA 30302, USA
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Exercise in the metabolic syndrome. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:349710. [PMID: 22829955 PMCID: PMC3399489 DOI: 10.1155/2012/349710] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 05/13/2012] [Indexed: 02/06/2023]
Abstract
The metabolic syndrome is a clustering of obesity, diabetes, hyperlipidemia, and hypertension that is occurring in increasing frequency across the global population. Although there is some controversy about its diagnostic criteria, oxidative stress, which is defined as imbalance between the production and inactivation of reactive oxygen species, has a major pathophysiological role in all the components of this disease. Oxidative stress and consequent inflammation induce insulin resistance, which likely links the various components of this disease. We briefly review the role of oxidative stress as a major component of the metabolic syndrome and then discuss the impact of exercise on these pathophysiological pathways. Included in this paper is the effect of exercise in reducing fat-induced inflammation, blood pressure, and improving muscular metabolism.
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Berwick ZC, Dick GM, Tune JD. Heart of the matter: coronary dysfunction in metabolic syndrome. J Mol Cell Cardiol 2012; 52:848-56. [PMID: 21767548 PMCID: PMC3206994 DOI: 10.1016/j.yjmcc.2011.06.025] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 06/16/2011] [Accepted: 06/30/2011] [Indexed: 12/14/2022]
Abstract
Metabolic syndrome (MetS) is a collection of risk factors including obesity, dyslipidemia, insulin resistance/impaired glucose tolerance, and/or hypertension. The incidence of obesity has reached pandemic levels, as ~20-30% of adults in most developed countries can be classified as having MetS. This increased prevalence of MetS is critical as it is associated with a two-fold elevated risk for cardiovascular disease. Although the pathophysiology underlying this increase in disease has not been clearly defined, recent evidence indicates that alterations in the control of coronary blood flow could play an important role. The purpose of this review is to highlight current understanding of the effects of MetS on regulation of coronary blood flow and to outline the potential mechanisms involved. In particular, the role of neurohumoral modulation via sympathetic α-adrenoceptors and the renin-angiotensin-aldosterone system (RAAS) are explored. Alterations in the contribution of end-effector K(+), Ca(2+), and transient receptor potential (TRP) channels are also addressed. Finally, future perspectives and potential therapeutic targeting of the microcirculation in MetS are discussed. This article is part of a Special Issue entitled "Coronary Blood Flow".
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Affiliation(s)
- Zachary C. Berwick
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Gregory M. Dick
- Department of Exercise Physiology Center for Cardiovascular and Respiratory Sciences West Virginia University School of Medicine
| | - Johnathan D. Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202
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Berwick ZC, Moberly SP, Kohr MC, Morrical EB, Kurian MM, Dick GM, Tune JD. Contribution of voltage-dependent K+ and Ca2+ channels to coronary pressure-flow autoregulation. Basic Res Cardiol 2012; 107:264. [PMID: 22466959 DOI: 10.1007/s00395-012-0264-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 02/21/2012] [Accepted: 03/08/2012] [Indexed: 11/30/2022]
Abstract
The mechanisms responsible for coronary pressure-flow autoregulation, a critical physiologic phenomenon that maintains coronary blood flow relatively constant in the presence of changes in perfusion pressure, remain poorly understood. This investigation tested the hypothesis that voltage-sensitive K(+) (K(V)) and Ca(2+) (Ca(V)1.2) channels play a critical role in coronary pressure-flow autoregulation in vivo. Experiments were performed in open-chest, anesthetized Ossabaw swine during step changes in coronary perfusion pressure (CPP) from 40 to 140 mmHg before and during inhibition of K(V) channels with 4-aminopyridine (4AP, 0.3 mM, ic) or Ca(V)1.2 channels with diltiazem (10 μg/min, ic). 4AP significantly decreased vasodilatory responses to H(2)O(2) (0.3-10 μM, ic) and coronary flow at CPPs = 60-140 mmHg. This decrease in coronary flow was associated with diminished ventricular contractile function (dP/dT) and myocardial oxygen consumption. However, the overall sensitivity to changes in CPP from 60 to 100 mmHg (i.e. autoregulatory gain; Gc) was unaltered by 4-AP administration (Gc = 0.46 ± 0.11 control vs. 0.46 ± 0.06 4-AP). In contrast, inhibition of Ca(V)1.2 channels progressively increased coronary blood flow at CPPs > 80 mmHg and substantially diminished coronary Gc to -0.20 ± 0.11 (P < 0.01), with no effect on contractile function or oxygen consumption. Taken together, these findings demonstrate that (1) K(V) channels tonically contribute to the control of microvascular resistance over a wide range of CPPs, but do not contribute to coronary responses to changes in pressure; (2) progressive activation of Ca(V)1.2 channels with increases in CPP represents a critical mechanism of coronary pressure-flow autoregulation.
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Affiliation(s)
- Zachary C Berwick
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, 46202, USA
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Kinoshita H, Matsuda N, Iranami H, Ogawa K, Hatakeyama N, Azma T, Kawahito S, Yamazaki M. Isoflurane pretreatment preserves adenosine triphosphate-sensitive K(+) channel function in the human artery exposed to oxidative stress caused by high glucose levels. Anesth Analg 2012; 115:54-61. [PMID: 22467893 DOI: 10.1213/ane.0b013e318254270d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Adenosine triphosphate (ATP)-sensitive K(+) channels contribute to significant regulatory mechanisms related to organ blood flow in both physiological and pathological conditions. High glucose impairs arterial ATP-sensitive K(+) channel activity via superoxide production. However, the effects of anesthetics on this pathological process have not been evaluated in humans. In the present study, we investigated whether pretreatment with the volatile anesthetic isoflurane preserves ATP-sensitive K(+) channel activity in the human artery exposed to oxidative stress caused by high glucose. METHODS All experiments were performed using human omental arteries without endothelium in the presence of d-glucose (5.5 mmol/L). Some arteries were treated with isoflurane (1.15% or 2.3%) in combination with d- or l-glucose (20 mmol/L) for 60 minutes, and then only isoflurane was discontinued. Relaxation and hyperpolarization of arterial segments in response to an ATP-sensitive K(+) channel opener levcromakalim were evaluated using the isometric force recording or electrophysiological study, respectively. Superoxide production was determined by dihydroethidium fluorescence. Immunohistochemical analysis for a subunit of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase p47phox was performed. Data were evaluated using repeated-measures analysis of variance or a factorial analysis of variance as appropriate, followed by Scheffé test. RESULTS The ATP-sensitive K(+) channel antagonist glibenclamide (10(-6) mol/L) abolished relaxation induced by cumulative addition of levcromakalim (10(-8) to 10(-5) mol/L) in arteries treated with l-glucose (20 mmol/L). Incubation with d-glucose (20 mmol/L) impaired the vasorelaxation induced by levcromakalim. The selective NADPH oxidase NOX2 inhibitor gp91ds-tat (10(-6) mol/L) and pretreatment with isoflurane (1.15% and 2.3%) restored relaxation in response to levcromakalim in arteries treated with d-glucose (20 mmol/L). Isoflurane (2.3%), gp91ds-tat (10(-6) mol/L), and their combination similarly restored hyperpolarization in response to levcromakalim (3 × 10(-6) mol/L) in arteries treated with d-glucose (20 mmol/L). Along with these results, isoflurane (2.3%) reduced superoxide production and the intracellular mobilization of the cytosolic NOX2 subunit p47phox toward smooth muscle cell membrane in arteries treated with d-glucose (20 mmol/L). CONCLUSIONS We have demonstrated for the first time a beneficial effect from the pretreatment with isoflurane on the isolated human artery. Pretreatment with isoflurane preserves ATP-sensitive K(+) channel activity in the human omental artery exposed to oxidative stress induced by high glucose, whereas the effect seems to be mediated by NADPH oxidase inhibition. Volatile anesthetics may protect human visceral arteries from malfunction caused by oxidative stress.
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Affiliation(s)
- Hiroyuki Kinoshita
- Department of Anesthesiology, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-0012, Japan.
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Lu AD, Wang JF, Chen YH, Hou LL, Zhou XJ, Bian JJ, Wang JJ, Zhu KM. Nitric Oxide and ATP-Sensitive Potassium Channels Mediate Lipopolysaccharide-Induced Depression of Central Respiratory-Like Activity in Brain Slices. Neurosignals 2012; 20:103-11. [DOI: 10.1159/000330841] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 07/14/2011] [Indexed: 11/19/2022] Open
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Golbidi S, Badran M, Laher I. Diabetes and alpha lipoic Acid. Front Pharmacol 2011; 2:69. [PMID: 22125537 PMCID: PMC3221300 DOI: 10.3389/fphar.2011.00069] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 10/18/2011] [Indexed: 12/25/2022] Open
Abstract
Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E, and glutathione. It also boosts antioxidant defense system through Nrf-2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy.
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Affiliation(s)
- Saeid Golbidi
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia Vancouver, BC, Canada
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Influence of obesity and metabolic dysfunction on the endothelial control in the coronary circulation. J Mol Cell Cardiol 2011; 52:840-7. [PMID: 21889942 DOI: 10.1016/j.yjmcc.2011.08.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 08/17/2011] [Accepted: 08/18/2011] [Indexed: 02/07/2023]
Abstract
Diseases of the coronary circulation remain the leading cause of death in Western society despite impressive advances in diagnosis, pharmacotherapy and post-event management. Part of this statistic likely stems from a parallel increase in the prevalence of obesity and metabolic dysfunction, both significant risk factors for coronary disease. Obesity and diabetes pose unique challenges for the heart and their impact on the coronary vasculature remains incompletely understood. The vascular endothelium is a major interface between arterial function and the physical and chemical components of blood flow. Proper function of the endothelium is necessary to preserve hemostasis, maintain vascular tone and limit the extent of vascular diseases such as atherosclerosis. Given its central role in vascular health, endothelial dysfunction has been the source of considerable research interest in diabetes and obesity. In the current review, we will examine the pathologic impact of obesity and diabetes on coronary function and the extent to which these two factors impact endothelial function. This article is part of a Special Issue entitled "Coronary Blood Flow".
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Berwick ZC, Dick GM, Moberly SP, Kohr MC, Sturek M, Tune JD. Contribution of voltage-dependent K⁺ channels to metabolic control of coronary blood flow. J Mol Cell Cardiol 2011; 52:912-9. [PMID: 21771599 DOI: 10.1016/j.yjmcc.2011.07.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 06/27/2011] [Accepted: 07/02/2011] [Indexed: 01/12/2023]
Abstract
The purpose of this investigation was to test the hypothesis that K(V) channels contribute to metabolic control of coronary blood flow and that decreases in K(V) channel function and/or expression significantly attenuate myocardial oxygen supply-demand balance in the metabolic syndrome (MetS). Experiments were conducted in conscious, chronically instrumented Ossabaw swine fed either a normal maintenance diet or an excess calorie atherogenic diet that produces the clinical phenotype of early MetS. Data were obtained under resting conditions and during graded treadmill exercise before and after inhibition of K(V) channels with 4-aminopyridine (4-AP, 0.3mg/kg, iv). In lean-control swine, 4-AP reduced coronary blood flow ~15% at rest and ~20% during exercise. Inhibition of K(V) channels also increased aortic pressure (P<0.01) while reducing coronary venous PO(2) (P<0.01) at a given level of myocardial oxygen consumption (MVO(2)). Administration of 4-AP had no effect on coronary blood flow, aortic pressure, or coronary venous PO(2) in swine with MetS. The lack of response to 4-AP in MetS swine was associated with a ~20% reduction in coronary K(V) current (P<0.01) and decreased expression of K(V)1.5 channels in coronary arteries (P<0.01). Together, these data demonstrate that K(V) channels play an important role in balancing myocardial oxygen delivery with metabolism at rest and during exercise-induced increases in MVO(2). Our findings also indicate that decreases in K(V) channel current and expression contribute to impaired control of coronary blood flow in the MetS. This article is part of a Special Issue entitled "Coronary Blood Flow".
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Affiliation(s)
- Zachary C Berwick
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Leo CH, Hart JL, Woodman OL. 3′,4′-Dihydroxyflavonol restores endothelium-dependent relaxation in small mesenteric artery from rats with type 1 and type 2 diabetes. Eur J Pharmacol 2011; 659:193-8. [DOI: 10.1016/j.ejphar.2011.03.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/22/2011] [Accepted: 03/15/2011] [Indexed: 02/07/2023]
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Pereira AC, Olivon VC, de Oliveira AM. Impaired calcium influx despite hyper-reactivity in contralateral carotid following balloon injury: eNOS involvement. Eur J Pharmacol 2010; 642:121-7. [DOI: 10.1016/j.ejphar.2010.05.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 03/25/2010] [Accepted: 05/06/2010] [Indexed: 11/24/2022]
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An Apparent Paradox: Attenuation of Phenylephrine-mediated Calcium Mobilization and Hyperreactivity to Phenylephrine in Contralateral Carotid After Balloon Injury. J Cardiovasc Pharmacol 2010; 56:162-70. [DOI: 10.1097/fjc.0b013e3181e571cd] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Irat AM, Aslamaci S, Karasu C, Ari N. Alteration of vascular reactivity in diabetic human mammary artery and the effects of thiazolidinediones. J Pharm Pharmacol 2010; 58:1647-53. [PMID: 17331329 DOI: 10.1211/jpp.58.12.0012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Vascular reactivity was investigated in endothelium-denuded human internal mammary artery (IMA) rings from type 2 diabetic patients. It was also investigated whether insulin sensitizer thiazolidinedione drugs, pioglitazone and rosiglitazone, can directly affect the reactivity of IMA. Using organ bath techniques, cumulative concentration-response curves to phenylephrine (PE), KCl, cromakalim (CRO) and sodium nitroprusside (SNP) were constructed in diabetic and non-diabetic IMA rings. Means of maximal responses (% Emax) and pEC50 values (sensitivity) were compared. Emax values and the sensitivity to PE and KCl were increased while KATP-channel-mediated relaxations were reduced significantly in diabetic rings compared with non-diabetic rings (n = 5–12, P < 0.05). No changes were observed for SNP responses (n = 5, P > 0.05). Incubations with pioglitazone (1 and 10 μM) and rosiglitazone (1 and 20 μM), for 30 min, did not affect KATP-channel-mediated relaxations (n = 5 each, P > 0.05). Pioglitazone partly inhibited pre-contractions of PE and KCl at 10 μM, rosiglitazone did not. Vascular dysfunction observed in diabetic IMA may be of specific importance since they are widely used as coronary bypass material. Thiazolidinedione drugs may not worsen arterial dilatation through KATP channels in ischaemic or hypoxic insults in diabetic patients who are prone to such conditions. Pioglitazone has vasorelaxant property in the grafts.
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Affiliation(s)
- Ali Murat Irat
- Department of Pharmacology, University of Ankara, Tandoğan 06100, Ankara, Turkey
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Wu GB, Zhou EX, Qing DX, Li J. Role of potassium channels in regulation of rat coronary arteriole tone. Eur J Pharmacol 2009; 620:57-62. [DOI: 10.1016/j.ejphar.2009.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Revised: 07/17/2009] [Accepted: 08/04/2009] [Indexed: 11/25/2022]
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Gupte RS, Floyd BC, Kozicky M, George S, Ungvari ZI, Neito V, Wolin MS, Gupte SA. Synergistic activation of glucose-6-phosphate dehydrogenase and NAD(P)H oxidase by Src kinase elevates superoxide in type 2 diabetic, Zucker fa/fa, rat liver. Free Radic Biol Med 2009; 47:219-28. [PMID: 19230846 PMCID: PMC2700195 DOI: 10.1016/j.freeradbiomed.2009.01.028] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 01/02/2009] [Accepted: 01/18/2009] [Indexed: 10/21/2022]
Abstract
Glucose metabolism through the glycolysis and hexosamine pathway has been shown to be altered in type 2 diabetes. However, the fate of glucose through the pentose phosphate pathway (PPP) is currently unclear. In this study, we determined whether the activity of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme in the PPP, is modulated in the liver of Zucker obese fa/fa rats (9-11 weeks of age). We found that G6PD expression and activity, NADPH levels, and 6-phosphogluconate generation were significantly increased in the liver of fa/fa rats. Inhibition of PI3 kinase and Src kinases decreased (p < 0.05) G6PD activity in the fa/fa but not in the lean rat liver, suggesting that G6PD activity is regulated by PI3/Src kinase signaling pathways. G6PD-derived NADPH increased (p < 0.05) superoxide anion levels by 70-90% in fa/fa vs lean rat liver, which was inhibited by the NADPH oxidase inhibitor gp91(ds-tat) (50 microM) and G6PD inhibitors 6-aminonicotinamide (1 mM) and dehydroepiandrosterone (100 microM), therefore indicating that elevated G6PD activity may be responsible for mediating superoxide generation. Interestingly, we also found a positive correlation between liver hypertrophy/increased G6PD activity (r2 = 0.77; p = 0.0009) and liver hypertrophy/superoxide production (r2 = 0.51; p = 0.0091) in fa/fa rats. Increased G6PD and NADPH oxidase expression and activity, in young hyperglycemic and hyperinsulinemic rats before the development of diabetes, seems to be a contributing factor in the induction of oxidative stress. Because inhibition of G6PD activity decreases oxidative stress, we conclude that G6PD behaves as a pro-oxidant in the fa/fa rat liver in type 2 diabetes.
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Affiliation(s)
- Rakhee S. Gupte
- Department of Biochemistry & Molecular Biology, University of South Alabama, Mobile, AL 36688
- Department of Physiology, New York Medical College, Valhalla, NY 10595
| | - Beverly C. Floyd
- Department of Physiology, New York Medical College, Valhalla, NY 10595
| | - Mark Kozicky
- Department of Physiology, New York Medical College, Valhalla, NY 10595
| | - Shimran George
- Department of Physiology, New York Medical College, Valhalla, NY 10595
| | - Zoltan I. Ungvari
- Department of Physiology, New York Medical College, Valhalla, NY 10595
| | - Vanessa Neito
- Department of Physiology, New York Medical College, Valhalla, NY 10595
| | - Michael S. Wolin
- Department of Physiology, New York Medical College, Valhalla, NY 10595
| | - Sachin A Gupte
- Department of Biochemistry & Molecular Biology, University of South Alabama, Mobile, AL 36688
- Department of Physiology, New York Medical College, Valhalla, NY 10595
- Address Correspondence to: Sachin A Gupte, MD, PhD, Department of Biochemistry & Molecular Biology, University of South Alabama, College of Medicine, 307 University Blvd N., Mobile, AL 36688, USA, Tel: (251) 460-6402; Fax: (251) 460-6850,
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Dong L, Xie MJ, Zhang P, Ji LL, Liu WC, Dong MQ, Gao F. Rotenone partially reverses decreased BK Ca currents in cerebral artery smooth muscle cells from streptozotocin-induced diabetic mice. Clin Exp Pharmacol Physiol 2009; 36:e57-64. [PMID: 19515065 DOI: 10.1111/j.1440-1681.2009.05222.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
1. Reactive oxygen species (ROS) cause vascular complications and impair vasodilation in diabetes mellitus. Large-conductance Ca(2+)-activated potassium channels (BK(Ca)) modulate vascular tone and play an important negative feedback role in vasoconstriction. In the present study, we tested the hypothesis that ROS regulate the function of BK(Ca) in diabetic cerebral artery smooth muscle cells. 2. Diabetes was induced in male BALB/c mice by injection of streptozotocin (STZ; 180 mg/kg, i.p., dissolved in sterile saline). Control and diabetic mice were treated with 12.7 micromol/L rotenone, an inhibitor of the mitochondrial electron transport chain complex I, or placebo every other day for 5 weeks. The whole-cell patch clamp-technique and functional vasomotor methods were used to record BK(Ca) currents and myogenic tone of cerebral artery smooth muscle cells. 3. In the diabetic group, there was a significant decrease in spontaneous transient outward currents in cerebral artery smooth muscle cells compared with control. Although the currents were only moderately increased in rotenone-treated diabetic mice, they remained significantly lower than in the control group. Furthermore, the macroscopic BK(Ca) currents that were decreased in diabetic mice were partially recovered in rotenone-treated diabetic mice (P < 0.05 vs untreated diabetic group). 4. The posterior cerebral artery from diabetic mice had a significantly higher myogenic tone than the control group, but this impaired contraction was partially reversed in the rotenone-treated diabetic group (P < 0.05 vs untreated diabetic group). 5. The H(2)O(2) concentration was significantly increased in cerebral arteries from diabetic mice compared with control. This increase in H(2)O(2) was significantly blunted by rotenone treatment. 6. In conclusion, rotenone partially reverses the decreased macroscopic BK(Ca) currents in STZ-induced Type 1 diabetic mice and this reversal of BK(Ca) currents may be related to the inhibitory effects of rotenone on H(2)O(2) production. Reactive oxygen species, particularly H(2)O(2), are important regulators of BK(Ca) channels and myogenic tone in diabetic cerebral artery.
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Affiliation(s)
- Ling Dong
- Department of Physiology, Fourth Military Medical University, Xi'an 710032, China
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Serpillon S, Floyd BC, Gupte RS, George S, Kozicky M, Neito V, Recchia F, Stanley W, Wolin MS, Gupte SA. Superoxide production by NAD(P)H oxidase and mitochondria is increased in genetically obese and hyperglycemic rat heart and aorta before the development of cardiac dysfunction. The role of glucose-6-phosphate dehydrogenase-derived NADPH. Am J Physiol Heart Circ Physiol 2009; 297:H153-62. [PMID: 19429815 DOI: 10.1152/ajpheart.01142.2008] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Increased oxidative stress is a known cause of cardiac dysfunction in animals and patients with diabetes, but the sources of reactive oxygen species [e.g., superoxide anion (O(2)(-))] and the mechanisms underlying O(2)(-) production in diabetic hearts are not clearly understood. Our aim was to determine whether NADPH oxidase (Nox) is a source of O(2)(-) and whether glucose-6-phosphate dehydrogenase (G6PD)-derived NADPH plays a role in augmenting O(2)(-) generation in diabetes. We assessed cardiac function, Nox and G6PD activities, NADPH levels, and the activities of antioxidant enzymes in heart homogenates from young (9-11 wk old) Zucker lean and obese (fa/fa) rats. We found that myocardial G6PD activity was significantly higher in fa/fa than in lean rats, whereas superoxide dismutase and glutathione peroxidase activities were decreased (P < 0.05). O(2)(-) levels were elevated (70-90%; P < 0.05) in the diabetic heart, and this elevation was blocked by the Nox inhibitor gp-91(ds-tat) (50 microM) or by the mitochondrial respiratory chain inhibitors antimycin (10 microM) and rotenone (50 microM). Inhibition of G6PD by 6-aminonicotinamide (5 mM) and dihydroepiandrosterone (100 microM) also reduced (P < 0.05) O(2)(-) production. Notably, the activities of Nox and G6PD in the fa/fa rat heart were inhibited by chelerythrine, a protein kinase C inhibitor. Although we detected no changes in stroke volume, cardiac output, or ejection fraction, left ventricular diameter was slightly increased during diastole and systole, and left ventricular posterior wall thickness was decreased during systole (P < 0.05) in Zucker fa/fa rats. Our findings suggest that in a model of severe hyperlipidema and hyperglycemia Nox-derived O(2)(-) generation in the myocardium is fueled by elevated levels of G6PD-derived NADPH. Similar mechanisms were found to activate O(2)(-) production and induce endothelial dysfunction in aorta. Thus G6PD may be a useful therapeutic target for treating the cardiovascular disease associated with type 2 diabetes, if second-generation drugs specifically reducing the activity of G6PD to near normal levels are developed.
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Affiliation(s)
- Sabrina Serpillon
- Department of Physiology, New York Medical College, Valhalla, NY, USA
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Nadeem A, Ponnoth DS, Ansari HR, Batchelor TP, Dey RD, Ledent C, Mustafa SJ. A2A adenosine receptor deficiency leads to impaired tracheal relaxation via NADPH oxidase pathway in allergic mice. J Pharmacol Exp Ther 2009; 330:99-108. [PMID: 19395654 DOI: 10.1124/jpet.109.151613] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A(2A) adenosine receptor (A(2A)AR) has been shown to suppress superoxide generation in leukocytes via the cAMP-protein kinase A (PKA) pathway. However, no study has yet explored the role of A(2A)AR in relation to NADPH oxidase in murine tracheas in vitro, which may lead to altered smooth muscle relaxation in asthma. Therefore, the present study evaluated the effects of A(2A)AR deficiency on the NADPH oxidase pathway in tracheas of A(2A) wild-type (WT) and A(2A) knockout (KO) mice. A(2A)WT mice were sensitized with ovalbumin (30 microg i.p.) on days 1 and 6, followed by 5% ovalbumin aerosol challenge on days 11, 12, and 13. A(2A)AR (gene and protein expression), cAMP, and phosphorylated PKA (p-PKA) levels were decreased in A(2A)WT sensitized mice compared with controls. A(2A)KO mice also showed decreased cAMP and p-PKA levels. A(2A)WT sensitized and A(2A)KO control mice had increased gene and protein expression of NADPH oxidase subunits (p47phox and gp91phox) compared with the controls. Tracheal relaxation to specific A(2A)AR agonist, 4-[2-[[6-amino-9-(N-ethyl-beta-d-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride (CGS 21680), decreased in A(2A)WT sensitized mice compared with the controls, although it was absent in A(2A)KO mice. Pretreatment with NADPH oxidase inhibitors apocyanin/diphenyliodonium reversed the attenuated relaxation to CGS 21680 in A(2A)WT sensitized tracheas, whereas specific PKA inhibitor (9S,10S,12R)-2,3,9,10,11,12-hexahydro-10-hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-i] [1,6]benzodiazocine-10-carboxylic acid hexyl ester (KT 5720) blocked CGS 21680-induced relaxation. Tracheal reactive oxygen species (ROS) generation was also increased in A(2A)WT sensitized and A(2A)KO control mice compared with the controls. In conclusion, this study shows that A(2A)AR deficiency causes increased NADPH oxidase activation leading to decreased tracheal relaxation via altered cAMP-PKA signaling and ROS generation.
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Affiliation(s)
- A Nadeem
- Department of Physiology, Health Sciences Center North, West Virginia University, Morgantown, WV 26505-9229, USA.
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Rodriguez-Pallares J, Parga JA, Joglar B, Guerra MJ, Labandeira-Garcia JL. The Mitochondrial ATP-Sensitive Potassium Channel Blocker 5-Hydroxydecanoate Inhibits Toxicity of 6-Hydroxydopamine on Dopaminergic Neurons. Neurotox Res 2009; 15:82-95. [DOI: 10.1007/s12640-009-9010-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 12/12/2008] [Accepted: 12/17/2008] [Indexed: 12/21/2022]
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Félétou M. Calcium-activated potassium channels and endothelial dysfunction: therapeutic options? Br J Pharmacol 2009; 156:545-62. [PMID: 19187341 DOI: 10.1111/j.1476-5381.2009.00052.x] [Citation(s) in RCA: 187] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The three subtypes of calcium-activated potassium channels (K(Ca)) of large, intermediate and small conductance (BK(Ca), IK(Ca) and SK(Ca)) are present in the vascular wall. In healthy arteries, BK(Ca) channels are preferentially expressed in vascular smooth muscle cells, while IK(Ca) and SK(Ca) are preferentially located in endothelial cells. The activation of endothelial IK(Ca) and SK(Ca) contributes to nitric oxide (NO) generation and is required to elicit endothelium-dependent hyperpolarizations. In the latter responses, the hyperpolarization of the smooth muscle cells is evoked either via electrical coupling through myo-endothelial gap junctions or by potassium ions, which by accumulating in the intercellular space activate the inwardly rectifying potassium channel Kir2.1 and/or the Na(+)/K(+)-ATPase. Additionally, endothelium-derived factors such as cytochrome P450-derived epoxyeicosatrienoic acids and under some circumstances NO, prostacyclin, lipoxygenase products and hydrogen peroxide (H(2)O(2)) hyperpolarize and relax the underlying smooth muscle cells by activating BK(Ca). In contrast, cytochrome P450-derived 20-hydroxyeicosatetraenoic acid and various endothelium-derived contracting factors inhibit BK(Ca). Aging and cardiovascular diseases are associated with endothelial dysfunctions that can involve a decrease in NO bioavailability, alterations of EDHF-mediated responses and/or enhanced production of endothelium-derived contracting factors. Because potassium channels are involved in these endothelium-dependent responses, activation of endothelial and/or smooth muscle K(Ca) could prevent the occurrence of endothelial dysfunction. Therefore, direct activators of these potassium channels or compounds that regulate their activity or their expression may be of some therapeutic interest. Conversely, blockers of IK(Ca) may prevent restenosis and that of BK(Ca) channels sepsis-dependent hypotension.
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Affiliation(s)
- Michel Félétou
- Department of Angiology, Institut de Recherches Servier, Suresnes, France.
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Activation of BKCa channels by nitric oxide prevents coronary artery endothelial dysfunction in ouabain-induced hypertensive rats. J Hypertens 2009; 27:83-91. [DOI: 10.1097/hjh.0b013e328317a7cf] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Morsy MA, Fouad AA. Mechanisms of gastroprotective effect of eugenol in indomethacin-induced ulcer in rats. Phytother Res 2008; 22:1361-6. [DOI: 10.1002/ptr.2502] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Kinoshita H, Matsuda N, Kaba H, Hatakeyama N, Azma T, Nakahata K, Kuroda Y, Tange K, Iranami H, Hatano Y. Roles of Phosphatidylinositol 3-Kinase-Akt and NADPH Oxidase in Adenosine 5′-Triphosphate–Sensitive K
+
Channel Function Impaired by High Glucose in the Human Artery. Hypertension 2008; 52:507-13. [DOI: 10.1161/hypertensionaha.108.118216] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study was designed to examine roles of the phosphatidylinositol 3-kinase-Akt pathway and reduced nicotinamide-adenine dinucleotide phosphate oxidases in the reduced ATP-sensitive K
+
channel function via superoxide produced by high glucose in the human artery. We evaluated the activity of the phosphatidylinositol 3-kinase-Akt pathway, as well as reduced nicotinamide-adenine dinucleotide phosphate oxidases, the intracellular levels of superoxide and ATP-sensitive K
+
channel function in the human omental artery without endothelium. Levels of the p85-α subunit and reduced nicotinamide-adenine dinucleotide phosphate oxidase subunits, including p47phox, p22phox, and Rac-1, increased in the membrane fraction from arteries treated with
d
-glucose (20 mmol/L) accompanied by increased intracellular superoxide production. High glucose simultaneously augmented Akt phosphorylation at Ser 473, as well as Thr 308 in the human vascular smooth muscle cells. A phosphatidylinositol 3-kinase inhibitor LY294002, as well as tiron and apocynin, restored vasorelaxation and hyperpolarization in response to an ATP-sensitive K
+
channel opener levcromakalim. Therefore, it can be concluded that the activation of the phosphatidylinositol 3-kinase-Akt pathway, in combination with the translocation of p47phox, p22phox, and Rac-1, contributes to the superoxide production induced by high glucose, resulting in the impairment of ATP-sensitive K
+
channel function in the human visceral artery.
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Affiliation(s)
- Hiroyuki Kinoshita
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Naoyuki Matsuda
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Hikari Kaba
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Noboru Hatakeyama
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Toshiharu Azma
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Katsutoshi Nakahata
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Yasuhiro Kuroda
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Kazuaki Tange
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Hiroshi Iranami
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Yoshio Hatano
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
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Gupte SA, Wolin MS. Oxidant and redox signaling in vascular oxygen sensing: implications for systemic and pulmonary hypertension. Antioxid Redox Signal 2008; 10:1137-52. [PMID: 18315496 PMCID: PMC2443404 DOI: 10.1089/ars.2007.1995] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
It has been well known for >100 years that systemic blood vessels dilate in response to decreases in oxygen tension (hypoxia; low PO2), and this response appears to be critical to supply blood to the stressed organ. Conversely, pulmonary vessels constrict to a decrease in alveolar PO2 to maintain a balance in the ventilation-to-perfusion ratio. Currently, although little question exists that the PO2 affects vascular reactivity and vascular smooth muscle cells (VSMCs) act as oxygen sensors, the molecular mechanisms involved in modulating the vascular reactivity are still not clearly understood. Many laboratories, including ours, have suggested that the intracellular calcium concentration ([Ca2+]i), which regulates vasomotor function, is controlled by free radicals and redox signaling, including NAD(P)H and glutathione (GSH) redox. In this review article, therefore, we discuss the implications of redox and oxidant alterations seen in pulmonary and systemic hypertension, and how key targets that control [Ca2+]i, such as ion channels, Ca2+ release from internal stores and uptake by the sarcoplasmic reticulum, and the Ca2+ sensitivity to the myofilaments, are regulated by changes in intracellular redox and oxidants associated with vascular PO2sensing in physiologic or pathophysiologic conditions.
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Affiliation(s)
- Sachin A Gupte
- Department of Physiology, New York Medical College, Valhalla, New York 10595, USA.
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Mitochondrial reactive oxygen species inactivate neuronal nicotinic acetylcholine receptors and induce long-term depression of fast nicotinic synaptic transmission. J Neurosci 2008; 28:1733-44. [PMID: 18272694 DOI: 10.1523/jneurosci.5130-07.2008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs), ligand-gated ion channels implicated in a variety of cognitive, motor, and sensory behaviours, are targeted to compartments rich in mitochondria, particularly postsynaptic domains and presynaptic terminals, exposing these receptors to reactive oxygen species (ROS) generated by oxidative phosphorylation. In addition, these receptors can become exposed to ROS during the progression of certain neurodegenerative diseases. Because ROS are known to modify several membrane proteins, including some types of ion channels, it raises the question of whether elevations in cytosolic ROS alter the function of nAChRs. To address this, we elevated ROS in cultured sympathetic neurons, directly by perfusing neurons intracellularly with ROS, indirectly by blocking the mitochondrial electron transport chain, or noninvasively by transient NGF removal; we then simultaneously measured changes in cytosolic ROS levels and whole-cell ACh-evoked currents. In addition, we elevated cytosolic ROS in postganglionic neurons in intact ganglia and measured changes in nerve-evoked EPSPs. Our experiments indicate that mild elevations in cytosolic ROS, including that produced by transient interruption of NGF signaling, induce a use-dependent, long-lasting rundown of ACh-evoked currents on cultured sympathetic neurons and a long-lasting depression of fast nerve-evoked EPSPs. We show that these effects of cytosolic ROS are specific to nAChRs on neurons and do not cause rundown of ACh-evoked currents on muscle. Our results demonstrate that elevations in cytosolic ROS inactivate neuronal nAChRs in a use-dependent manner and suggest that mild oxidative stress impairs mechanisms mediated by cholinergic nicotinic signaling at neuronal-neuronal synapses.
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