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Zhang Y, Xu Z, Shan M, Cao J, Zhou Y, Chen Y, Shi L. Arterial Smooth Muscle Cell AKAP150 Mediates Exercise-Induced Repression of Ca V1.2 Channel Function in Cerebral Arteries of Hypertensive Rats. Arterioscler Thromb Vasc Biol 2024; 44:1202-1221. [PMID: 38602101 DOI: 10.1161/atvbaha.124.319543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 03/28/2024] [Indexed: 04/12/2024]
Abstract
BACKGROUND Hypertension is a major, prevalent risk factor for the development and progression of cerebrovascular disease. Regular exercise has been recommended as an excellent choice for the large population of individuals with mild-to-moderate elevations in blood pressure, but the mechanisms that underlie its vascular-protective and antihypertensive effects remain unknown. Here, we describe a mechanism by which myocyte AKAP150 (A-kinase anchoring protein 150) inhibition induced by exercise training alleviates voltage-dependent L-type Ca2+ channel (CaV1.2) activity and restores cerebral arterial function in hypertension. METHODS Spontaneously hypertensive rats and newly generated smooth muscle-specific AKAP150 knockin mice were used to assess the role of myocyte AKAP150/CaV1.2 channel in regulating cerebral artery function after exercise intervention. RESULTS Activation of the AKAP150/PKCα (protein kinase Cα) signaling increased CaV1.2 activity and Ca2+ influx of cerebral arterial myocyte, thus enhancing vascular tone in spontaneously hypertensive rats. Smooth muscle-specific AKAP150 knockin mice were hypertensive with higher CaV1.2 channel activity and increased vascular tone. Furthermore, treatment of Ang II (angiotensin II) resulted in a more pronounced increase in blood pressure in smooth muscle-specific AKAP150 knockin mice. Exercise training significantly reduced arterial myocyte AKAP150 expression and alleviated CaV1.2 channel activity, thus restoring cerebral arterial function in spontaneously hypertensive rats and smooth muscle-specific AKAP150 knockin mice. AT1R (AT1 receptor) and AKAP150 were interacted closely in arterial myocytes. Exercise decreased the circulating Ang II and Ang II-involved AT1R-AKAP150 association in myocytes of hypertension. CONCLUSIONS The current study demonstrates that aerobic exercise ameliorates CaV1.2 channel function via inhibiting myocyte AKAP150, which contributes to reduced cerebral arterial tone in hypertension.
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MESH Headings
- Animals
- A Kinase Anchor Proteins/metabolism
- A Kinase Anchor Proteins/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Channels, L-Type/genetics
- Rats, Inbred SHR
- Hypertension/physiopathology
- Hypertension/metabolism
- Hypertension/genetics
- Cerebral Arteries/metabolism
- Cerebral Arteries/physiopathology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Male
- Myocytes, Smooth Muscle/metabolism
- Disease Models, Animal
- Physical Conditioning, Animal/physiology
- Protein Kinase C-alpha/metabolism
- Protein Kinase C-alpha/genetics
- Calcium Signaling
- Mice, Inbred C57BL
- Mice
- Rats
- Rats, Inbred WKY
- Angiotensin II
- Blood Pressure
- Signal Transduction
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Affiliation(s)
- Yanyan Zhang
- Department of Exercise Physiology (Y. Zhang, Z.X., M.S., J.C., Y. Zhou, Y.C., L.S.), Beijing Sport University, China
- Laboratory of Sports Stress and Adaptation of General Administration of Sport (Y. Zhang, L.S.), Beijing Sport University, China
- Key Laboratory of Physical Fitness and Exercise, Ministry of Education (Y. Zhang, L.S.), Beijing Sport University, China
| | - Zhaoxia Xu
- Department of Exercise Physiology (Y. Zhang, Z.X., M.S., J.C., Y. Zhou, Y.C., L.S.), Beijing Sport University, China
| | - Meiling Shan
- Department of Exercise Physiology (Y. Zhang, Z.X., M.S., J.C., Y. Zhou, Y.C., L.S.), Beijing Sport University, China
| | - Jiaqi Cao
- Department of Exercise Physiology (Y. Zhang, Z.X., M.S., J.C., Y. Zhou, Y.C., L.S.), Beijing Sport University, China
| | - Yang Zhou
- Department of Exercise Physiology (Y. Zhang, Z.X., M.S., J.C., Y. Zhou, Y.C., L.S.), Beijing Sport University, China
| | - Yu Chen
- Department of Exercise Physiology (Y. Zhang, Z.X., M.S., J.C., Y. Zhou, Y.C., L.S.), Beijing Sport University, China
| | - Lijun Shi
- Department of Exercise Physiology (Y. Zhang, Z.X., M.S., J.C., Y. Zhou, Y.C., L.S.), Beijing Sport University, China
- Laboratory of Sports Stress and Adaptation of General Administration of Sport (Y. Zhang, L.S.), Beijing Sport University, China
- Key Laboratory of Physical Fitness and Exercise, Ministry of Education (Y. Zhang, L.S.), Beijing Sport University, China
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Eguchi S, Torimoto K, Adebiyi A, Kanthakumar P, Bomfim GF, Wenceslau CF, Dahlen SA, Osei-Owusu P. Milestone Papers on Signal Transduction Mechanisms of Hypertension and Its Complications. Hypertension 2024; 81:977-990. [PMID: 38372140 PMCID: PMC11023792 DOI: 10.1161/hypertensionaha.123.21365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
To celebrate 100 years of American Heart Association-supported cardiovascular disease research, this review article highlights milestone papers that have significantly contributed to the current understanding of the signaling mechanisms driving hypertension and associated cardiovascular disorders. This article also includes a few of the future research directions arising from these critical findings. To accomplish this important mission, 4 principal investigators gathered their efforts to cover distinct yet intricately related areas of signaling mechanisms pertaining to the pathogenesis of hypertension. The renin-angiotensin system, canonical and novel contractile and vasodilatory pathways in the resistance vasculature, vascular smooth muscle regulation by membrane channels, and noncanonical regulation of blood pressure and vascular function will be described and discussed as major subjects.
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Affiliation(s)
- Satoru Eguchi
- Department of Cardiovascular Science, Lewis Katz School of Medicine, Temple University
- Sol Sherry Thrombosis Research Center, Lewis Katz School of Medicine, Temple University
| | - Keiichi Torimoto
- Department of Cardiovascular Science, Lewis Katz School of Medicine, Temple University
| | - Adebowale Adebiyi
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
- Department of Anesthesiology and Perioperative Medicine, University of Missouri, Columbia, Missouri
- NextGen Precision Health, University of Missouri, Columbia, Missouri
| | - Praghalathan Kanthakumar
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
- Department of Anesthesiology and Perioperative Medicine, University of Missouri, Columbia, Missouri
- NextGen Precision Health, University of Missouri, Columbia, Missouri
| | - Gisele F. Bomfim
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine
| | - Camilla Ferreira Wenceslau
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine
| | - Shelby A. Dahlen
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University
| | - Patrick Osei-Owusu
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University
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3
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Hou W, Yin S, Li P, Zhang L, Chen T, Qin D, Mustafa AU, Liu C, Song M, Qiu C, Xiong X, Wang J. Aberrant splicing of Ca V1.2 calcium channel induced by decreased Rbfox1 enhances arterial constriction during diabetic hyperglycemia. Cell Mol Life Sci 2024; 81:164. [PMID: 38575795 PMCID: PMC10995029 DOI: 10.1007/s00018-024-05198-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 02/23/2024] [Accepted: 03/04/2024] [Indexed: 04/06/2024]
Abstract
Diabetic hyperglycemia induces dysfunctions of arterial smooth muscle, leading to diabetic vascular complications. The CaV1.2 calcium channel is one primary pathway for Ca2+ influx, which initiates vasoconstriction. However, the long-term regulation mechanism(s) for vascular CaV1.2 functions under hyperglycemic condition remains unknown. Here, Sprague-Dawley rats fed with high-fat diet in combination with low dose streptozotocin and Goto-Kakizaki (GK) rats were used as diabetic models. Isolated mesenteric arteries (MAs) and vascular smooth muscle cells (VSMCs) from rat models were used to assess K+-induced arterial constriction and CaV1.2 channel functions using vascular myograph and whole-cell patch clamp, respectively. K+-induced vasoconstriction is persistently enhanced in the MAs from diabetic rats, and CaV1.2 alternative spliced exon 9* is increased, while exon 33 is decreased in rat diabetic arteries. Furthermore, CaV1.2 channels exhibit hyperpolarized current-voltage and activation curve in VSMCs from diabetic rats, which facilitates the channel function. Unexpectedly, the application of glycated serum (GS), mimicking advanced glycation end-products (AGEs), but not glucose, downregulates the expression of the splicing factor Rbfox1 in VSMCs. Moreover, GS application or Rbfox1 knockdown dynamically regulates alternative exons 9* and 33, leading to facilitated functions of CaV1.2 channels in VSMCs and MAs. Notably, GS increases K+-induced intracellular calcium concentration of VSMCs and the vasoconstriction of MAs. These results reveal that AGEs, not glucose, long-termly regulates CaV1.2 alternative splicing events by decreasing Rbfox1 expression, thereby enhancing channel functions and increasing vasoconstriction under diabetic hyperglycemia. This study identifies the specific molecular mechanism for enhanced vasoconstriction under hyperglycemia, providing a potential target for managing diabetic vascular complications.
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Affiliation(s)
- Wei Hou
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
- The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou School of Clinical Medicine, Nanjing Medical University, Taizhou, Jiangsu, China
| | - Shumin Yin
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Pengpeng Li
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ludan Zhang
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Tiange Chen
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Dongxia Qin
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Atta Ul Mustafa
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Caijie Liu
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Miaomiao Song
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Cheng Qiu
- Nanjing Comprehensive Stroke Center, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiaoqing Xiong
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China.
- The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou School of Clinical Medicine, Nanjing Medical University, Taizhou, Jiangsu, China.
| | - Juejin Wang
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China.
- The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou School of Clinical Medicine, Nanjing Medical University, Taizhou, Jiangsu, China.
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Hu XQ, Zhang L. Oxidative Regulation of Vascular Ca v1.2 Channels Triggers Vascular Dysfunction in Hypertension-Related Disorders. Antioxidants (Basel) 2022; 11:antiox11122432. [PMID: 36552639 PMCID: PMC9774363 DOI: 10.3390/antiox11122432] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/28/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
Blood pressure is determined by cardiac output and peripheral vascular resistance. The L-type voltage-gated Ca2+ (Cav1.2) channel in small arteries and arterioles plays an essential role in regulating Ca2+ influx, vascular resistance, and blood pressure. Hypertension and preeclampsia are characterized by high blood pressure. In addition, diabetes has a high prevalence of hypertension. The etiology of these disorders remains elusive, involving the complex interplay of environmental and genetic factors. Common to these disorders are oxidative stress and vascular dysfunction. Reactive oxygen species (ROS) derived from NADPH oxidases (NOXs) and mitochondria are primary sources of vascular oxidative stress, whereas dysfunction of the Cav1.2 channel confers increased vascular resistance in hypertension. This review will discuss the importance of ROS derived from NOXs and mitochondria in regulating vascular Cav1.2 and potential roles of ROS-mediated Cav1.2 dysfunction in aberrant vascular function in hypertension, diabetes, and preeclampsia.
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Goto K, Kitazono T. Chloride Ions, Vascular Function and Hypertension. Biomedicines 2022; 10:biomedicines10092316. [PMID: 36140417 PMCID: PMC9496098 DOI: 10.3390/biomedicines10092316] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/10/2022] [Accepted: 09/15/2022] [Indexed: 11/26/2022] Open
Abstract
Blood pressure is determined by cardiac output and systemic vascular resistance, and mediators that induce vasoconstriction will increase systemic vascular resistance and thus elevate blood pressure. While peripheral vascular resistance reflects a complex interaction of multiple factors, vascular ion channels and transporters play important roles in the regulation of vascular tone by modulating the membrane potential of vascular cells. In vascular smooth muscle cells, chloride ions (Cl−) are a type of anions accumulated by anion exchangers and the anion–proton cotransporter system, and efflux of Cl− through Cl− channels depolarizes the membrane and thereby triggers vasoconstriction. Among these Cl− regulatory pathways, emerging evidence suggests that upregulation of the Ca2+-activated Cl− channel TMEM16A in the vasculature contributes to the increased vascular contractility and elevated blood pressure in hypertension. A robust accumulation of intracellular Cl− in vascular smooth muscle cells through the increased activity of Na+–K+–2Cl− cotransporter 1 (NKCC1) during hypertension has also been reported. Thus, the enhanced activity of both TMEM16A and NKCC1 could act additively and sequentially to increase vascular contractility and hence blood pressure in hypertension. In this review, we discuss recent findings regarding the role of Cl− in the regulation of vascular tone and arterial blood pressure and its association with hypertension, with a particular focus on TMEM16A and NKCC1.
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Affiliation(s)
- Kenichi Goto
- Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
- Correspondence:
| | - Takanari Kitazono
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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6
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Diminished Rbfox1 increases vascular constriction by dynamically regulating alternative splicing of CaV1.2 calcium channel in hypertension. Clin Sci (Lond) 2022; 136:803-817. [PMID: 35543237 DOI: 10.1042/cs20220226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/08/2022] [Accepted: 05/10/2022] [Indexed: 11/17/2022]
Abstract
Calcium influx from depolarized CaV1.2 calcium channels triggers the contraction of vascular smooth muscle cells (VSMCs), which is important for maintaining vascular myogenic tone and blood pressure. The function of CaV1.2 channel can be subtly modulated by alternative splicing (AS), and its aberrant splicing involves in the pathogenesis of multiple cardiovascular diseases. The RNA binding protein Rbfox1 is reported to regulate the AS events of CaV1.2 channel in the neuronal development, but its potential roles in vascular CaV1.2 channels and vasoconstriction remain undefined. Here, we detect Rbfox1 is expressed in rat vascular smooth muscles. Moreover, the protein level of Rbfox1 is dramatically decreased in the hypertensive small arteries from spontaneously hypertensive rats in comparison to normotensive ones from Wistar-Kyoto rats. In VSMCs, Rbfox1 could dynamically regulate the AS of CaV1.2 exons 9* and 33. By whole-cell patch clamp, we identify knockdown of Rbfox1 induces the hyperpolarization of CaV1.2 current-voltage relationship curve in VSMCs. Furthermore, siRNA-mediated knockdown of Rbfox1 increases the K+-induced constriction of rat mesenteric arteries. In summary, our results indicate Rbfox1 modulates vascular constriction by dynamically regulating CaV1.2 alternative exons 9* and 33. Therefore, our work elucidates the underlying mechanisms for CaV1.2 channels regulation and provides a potential therapeutic target for hypertension.
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7
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Li S, Chen Y, Zhang Y, Zhang H, Wu Y, He H, Gong L, Zeng F, Shi L. Exercise during pregnancy enhances vascular function via epigenetic repression of Ca V1.2 channel in offspring of hypertensive rats. Life Sci 2019; 231:116576. [PMID: 31211998 DOI: 10.1016/j.lfs.2019.116576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/08/2019] [Accepted: 06/14/2019] [Indexed: 12/22/2022]
Abstract
AIMS Studies suggest that cardiovascular function in offspring can be epigenetically programmed by environmental changes during pregnancy. CaV1.2 channel plays a major role in the regulation of the vascular tone. This study investigated the effects and underlying mechanisms of exercise during pregnancy on CaV1.2 channel functional remodeling in hypertensive offspring. MAIN METHODS Exercise groups were subjected to swimming at the first day of pregnancy and on a regular schedule thereafter for 3 weeks. Their offspring (6-month-old, male) were tested for baseline blood pressure, cardiovascular response, and vascular tone of the mesenteric artery. Mesenteric artery smooth muscle cells were taken to study the whole-cell current of the CaV1.2 channel. Western blotting, RT-PCR and DNA bisulfite sequencing PCR were performed to study the protein, mRNA expression and DNA methylation of the CaV1.2 channel α1C subunit. KEY FINDINGS Exercise during pregnancy reduced the pressor response to norepinephrine and Bay K8644, and the depressor response to nifedipine in offspring of hypertensive rats. The level of the CaV1.2 channel in norepinephrine-induced vasoconstrictions decreased, and the whole-cell current of the CaV1.2 channel declined in the SHR-EX group. Further studies found that exercise during pregnancy reduced the protein and mRNA expression of the CaV1.2 channel α1C subunit and upregulated DNA methylation of the Cacna1c gene promoter region in the hypertensive offspring. SIGNIFICANCE These data suggest that exercise during pregnancy improves vascular functional remodeling in offspring of hypertensive rats, downregulating the CaV1.2 channel function and protein expression, a change that is most likely caused by DNA methylation.
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Affiliation(s)
- Shanshan Li
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China; China Institute of Sport and Health Science, Beijing Sport University, Beijing 100084, China
| | - Yu Chen
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Yanyan Zhang
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Huirong Zhang
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Ying Wu
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Hui He
- China Institute of Sport and Health Science, Beijing Sport University, Beijing 100084, China
| | - Lijing Gong
- China Institute of Sport and Health Science, Beijing Sport University, Beijing 100084, China
| | - Fanxing Zeng
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Lijun Shi
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China; China Institute of Sport and Health Science, Beijing Sport University, Beijing 100084, China.
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Chottova Dvorakova M. Distribution and Function of Neuropeptides W/B Signaling System. Front Physiol 2018; 9:981. [PMID: 30087623 PMCID: PMC6067035 DOI: 10.3389/fphys.2018.00981] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 07/03/2018] [Indexed: 12/11/2022] Open
Abstract
Neuropeptide W (NPW) and neuropeptide B (NPB) are two structurally and functionally related regulatory peptides, which are highly expressed in several brain regions and, additionally, in some peripheral tissues. Nevertheless, their distributions in the tissues are not similar. They act on target tissues via two subtypes of G protein-coupled receptors which are designated as NPBWR1 (GPR7) and NPBWR2 (GPR8), respectively, and possess different binding affinities. NPB activates NPBWR1, whereas NPW stimulates both the receptors with similar potency. Both of these peptides takes a part in the central regulation of neuroendocrine axes, feeding behavior, energy homeostasis, cardiovascular functions, circadian rhythm, pain sensation, modulation of inflammatory pain, and emotions. Over the past few years, studies have shown that NPB is also involved in sleep regulation. On the contrary, NPW participates in regulation of vascular myogenic tone, inhibits gastric tension sensitive vagal afferents and insulin secretion. Also, expression of NPW in the stomach is regulated by feeding. Abovementioned findings clearly demonstrate the functional diversity among NPW versus NPB signaling systems. In this review, signal transduction pathways of NPW/NPB are critically evaluated and observed together with mapping of expression of their signaling systems.
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Affiliation(s)
- Magdalena Chottova Dvorakova
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czechia.,Department of Physiology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czechia
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9
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Unravelling the complexities of vascular smooth muscle ion channels: Fine tuning of activity by ancillary subunits. Pharmacol Ther 2017; 178:57-66. [PMID: 28336473 DOI: 10.1016/j.pharmthera.2017.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Which ion channel is the most important for regulating vascular tone? Which one is responsible for controlling the resting membrane potential or repolarization? Which channels are recruited by different intracellular signalling pathways or change in certain vascular diseases? Many different ion channels have been identified in the vasculature over the years and claimed as future therapeutic targets. Unfortunately, several of these ion channels are not just found in the vasculature, with many of them also found to have prominent functional roles in different organs of the body, which then leads to off-target effects. As cardiovascular diseases are expected to increase worldwide to epidemic proportions, ion channel research and the hunt for the next major therapeutic target to treat different vascular diseases has never been more important. However, I believe that the question we should now be asking is: which ancillary subunits are involved in regulating specific ion channels in the vasculature and do they have the potential to be new therapeutic targets?
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10
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Measuring T-Type Calcium Channel Currents in Isolated Vascular Smooth Muscle Cells. Methods Mol Biol 2017. [PMID: 28116717 DOI: 10.1007/978-1-4939-6625-7_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Patch clamp electrophysiology is a powerful tool that has been important in isolating and characterizing the ion channels that govern cellular excitability under physiological and pathophysiological conditions. The ability to enzymatically dissociate blood vessels and acutely isolate vascular smooth muscle cells has enabled the application of patch clamp electrophysiology to the identification of diverse voltage dependent ion channels that ultimately control vasoconstriction and vasodilation. Since intraluminal pressure results in depolarization of vascular smooth muscle, the channels that control the voltage dependent influx of extracellular calcium are of particular interest. This chapter describes methods for isolating smooth muscle cells from resistance vessels, and for recording, isolating, and characterizing voltage dependent calcium channel currents, using patch clamp electrophysiological and pharmacological protocols.
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11
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Bencze M, Behuliak M, Vavřínová A, Zicha J. Altered contractile responses of arteries from spontaneously hypertensive rat: The role of endogenous mediators and membrane depolarization. Life Sci 2016; 166:46-53. [DOI: 10.1016/j.lfs.2016.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 09/19/2016] [Accepted: 10/05/2016] [Indexed: 11/25/2022]
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12
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Liao J, Zhang Y, Ye F, Zhang L, Chen Y, Zeng F, Shi L. Epigenetic regulation of L-type voltage-gated Ca 2+ channels in mesenteric arteries of aging hypertensive rats. Hypertens Res 2016; 40:441-449. [PMID: 27881847 DOI: 10.1038/hr.2016.167] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 09/18/2016] [Accepted: 10/16/2016] [Indexed: 01/26/2023]
Abstract
Accumulating evidence has shown that epigenetic regulation is involved in hypertension and aging. L-type voltage-gated Ca2+ channels (LTCCs), the dominant channels in vascular myocytes, greatly contribute to arteriole contraction and blood pressure (BP) control. We investigated the dynamic changes and epigenetic regulation of LTCC in the mesenteric arteries of aging hypertensive rats. LTCC function was evaluated by using microvascular rings and whole-cell patch-clamp in the mesenteric arteries of male Wistar-Kyoto rats and spontaneously hypertensive rats at established hypertension (3 month old) and an aging stage (16 month old), respectively. The expression of the LTCC α1C subunit was determined in the rat mesenteric microcirculation. The expression of miR-328, which targets α1C mRNA, and the DNA methylation status at the promoter region of the α1C gene (CACNA1C) were also determined. In vitro experiments were performed to assess α1C expression after transfection of the miR-328 mimic into cultured vascular smooth muscle cells (VSMCs). The results showed that hypertension superimposed with aging aggravated BP and vascular remodeling. Both LTCC function and expression were significantly increased in hypertensive arteries and downregulated with aging. miR-328 expression was inhibited in hypertension, but increased with aging. There was no significant difference in the mean DNA methylation of CACNA1C among groups, whereas methylation was enhanced in the hypertensive group at specific sites on a CpG island located upstream of the gene promoter. Overexpression of miR-328 inhibited the α1C level of cultured VSMCs within 48 h. The results of the present study indicate that the dysfunction of LTCCs may exert an epigenetic influence at both pre- and post-transcriptional levels during hypertension pathogenesis and aging progression. miR-328 negatively regulated LTCC expression in both aging and hypertension.
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Affiliation(s)
- Jingwen Liao
- Department of Exercise Physiology, Beijing Sport University, Beijing, China.,Department of Sport and Health Sciences, Guangzhou Institute of Physical Education, Guangzhou, China
| | - Yanyan Zhang
- Department of Exercise Physiology, Beijing Sport University, Beijing, China
| | - Fang Ye
- Department of Exercise Physiology, Beijing Sport University, Beijing, China
| | - Lin Zhang
- Department of Exercise Physiology, Beijing Sport University, Beijing, China
| | - Yu Chen
- Department of Exercise Physiology, Beijing Sport University, Beijing, China
| | - Fanxing Zeng
- Department of Exercise Physiology, Beijing Sport University, Beijing, China
| | - Lijun Shi
- Department of Exercise Physiology, Beijing Sport University, Beijing, China
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13
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DuPont JJ, McCurley A, Davel AP, McCarthy J, Bender SB, Hong K, Yang Y, Yoo JK, Aronovitz M, Baur WE, Christou DD, Hill MA, Jaffe IZ. Vascular mineralocorticoid receptor regulates microRNA-155 to promote vasoconstriction and rising blood pressure with aging. JCI Insight 2016; 1:e88942. [PMID: 27683672 DOI: 10.1172/jci.insight.88942] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hypertension is nearly universal yet poorly controlled in the elderly despite proven benefits of intensive treatment. Mice lacking mineralocorticoid receptors in smooth muscle cells (SMC-MR-KO) are protected from rising blood pressure (BP) with aging, despite normal renal function. Vasoconstriction is attenuated in aged SMC-MR-KO mice, thus they were used to explore vascular mechanisms that may contribute to hypertension with aging. MicroRNA (miR) profiling identified miR-155 as the most down-regulated miR with vascular aging in MR-intact but not SMC-MR-KO mice. The aging-associated decrease in miR-155 in mesenteric resistance vessels was associated with increased mRNA abundance of MR and of predicted miR-155 targets Cav1.2 (L-type calcium channel (LTCC) subunit) and angiotensin type-1 receptor (AgtR1). SMC-MR-KO mice lacked these aging-associated vascular gene expression changes. In HEK293 cells, MR repressed miR-155 promoter activity. In cultured SMCs, miR-155 decreased Cav1.2 and AgtR1 mRNA. Compared to MR-intact littermates, aged SMC-MR-KO mice had decreased systolic BP, myogenic tone, SMC LTCC current, mesenteric vessel calcium influx, LTCC-induced vasoconstriction and angiotensin II-induced vasoconstriction and oxidative stress. Restoration of miR-155 specifically in SMCs of aged MR-intact mice decreased Cav1.2 and AgtR1 mRNA and attenuated LTCC-mediated and angiotensin II-induced vasoconstriction and oxidative stress. Finally, in a trial of MR blockade in elderly humans, changes in serum miR-155 predicted the BP treatment response. Thus, SMC-MR regulation of miR-155, Cav1.2 and AgtR1 impacts vasoconstriction with aging. This novel mechanism identifies potential new treatment strategies and biomarkers to improve and individualize antihypertensive therapy in the elderly.
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Affiliation(s)
- Jennifer J DuPont
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Amy McCurley
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Ana P Davel
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA.,Department of Structural and Functional Biology, Institute of Biology, University of Campinas-UNICAMP, São Paulo, Brazil
| | - Joseph McCarthy
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Shawn B Bender
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA.,Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, Missouri, USA.,Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
| | - Kwangseok Hong
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA.,Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Yan Yang
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - Jeung-Ki Yoo
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Mark Aronovitz
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Wendy E Baur
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Demetra D Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Michael A Hill
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA.,Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Iris Z Jaffe
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
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14
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Modulation of CaV1.2 calcium channel by neuropeptide W regulates vascular myogenic tone via G protein-coupled receptor 7. J Hypertens 2015; 33:2431-42. [DOI: 10.1097/hjh.0000000000000723] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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15
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Exercise intensity-dependent reverse and adverse remodeling of voltage-gated Ca2+ channels in mesenteric arteries from spontaneously hypertensive rats. Hypertens Res 2015; 38:656-65. [DOI: 10.1038/hr.2015.56] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Revised: 02/11/2015] [Accepted: 03/03/2015] [Indexed: 02/06/2023]
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16
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Youm JB, Park KS, Jang YJ, Leem CH. Effects of streptozotocin and unilateral nephrectomy on L-type Ca2+ channels and membrane capacitance in arteriolar smooth muscle cells. Pflugers Arch 2014; 467:1689-97. [DOI: 10.1007/s00424-014-1604-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 08/26/2014] [Accepted: 08/29/2014] [Indexed: 11/30/2022]
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17
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Abstract
Ion channels and transporters are expressed in every living cell, where they participate in controlling a plethora of biological processes and physiological functions, such as excitation of cells in response to stimulation, electrical activities of cells, excitation-contraction coupling, cellular osmolarity, and even cell growth and death. Alterations of ion channels/transporters can have profound impacts on the cellular physiology associated with these proteins. Expression of ion channels/transporters is tightly regulated and expression deregulation can trigger abnormal processes, leading to pathogenesis, the channelopathies. While transcription factors play a critical role in controlling the transcriptome of ion channels/transporters at the transcriptional level by acting on the 5'-flanking region of the genes, microribonucleic acids (miRNAs), a newly discovered class of regulators in the gene network, are also crucial for expression regulation at the posttranscriptional level through binding to the 3'untranslated region of the genes. These small noncoding RNAs fine tune expression of genes involved in a wide variety of cellular processes. Recent studies revealed the role of miRNAs in regulating expression of ion channels/transporters and the associated physiological functions. miRNAs can target ion channel genes to alter cardiac excitability (conduction, repolarization, and automaticity) and affect arrhythmogenic potential of heart. They can modulate circadian rhythm, pain threshold, neuroadaptation to alcohol, brain edema, etc., through targeting ion channel genes in the neuronal systems. miRNAs can also control cell growth and tumorigenesis by acting on the relevant ion channel genes. Future studies are expected to rapidly increase to unravel a new repertoire of ion channels/transporters for miRNA regulation.
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Affiliation(s)
- Zhiguo Wang
- Harbin Medical University, Harbin, Heilongjiang, People's Republic of China.
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18
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Tajada S, Cidad P, Colinas O, Santana LF, López-López JR, Pérez-García MT. Down-regulation of CaV1.2 channels during hypertension: how fewer CaV1.2 channels allow more Ca(2+) into hypertensive arterial smooth muscle. J Physiol 2013; 591:6175-91. [PMID: 24167226 DOI: 10.1113/jphysiol.2013.265751] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Hypertension is a clinical syndrome characterized by increased arterial tone. Although the mechanisms are varied, the generally accepted view is that increased CaV1.2 channel function is a common feature of this pathological condition. Here, we investigated the mechanisms underlying vascular dysfunction in a mouse model of genetic hypertension. Contrary to expectation, we found that whole-cell CaV1.2 currents (ICa) were lower in hypertensive (BPH line) than normotensive (BPN line) myocytes. However, local CaV1.2 sparklet activity was higher in BPH cells, suggesting that the relatively low ICa in these cells was produced by a few hyperactive CaV1.2 channels. Furthermore, our data suggest that while the lower expression of the pore-forming α1c subunit of CaV1.2 currents underlies the lower ICa in BPH myocytes, the increased sparklet activity was due to a different composition in the auxiliary subunits of the CaV1.2 complexes. ICa currents in BPN cells were produced by channels composed of α1c/α2δ/β3 subunits, while in BPH myocytes currents were probably generated by the opening of channels formed by α1c/α2δ/β2 subunits. In addition, Ca(2+) sparks evoked large conductance, Ca(2+)-activated K(+) (BK) currents of lower magnitude in BPH than in BPN myocytes, because BK channels were less sensitive to Ca(2+). Our data are consistent with a model in which a decrease in the global number of CaV1.2 currents coexist with the existence of a subpopulation of highly active channels that dominate the resting Ca(2+) influx. The decrease in BK channel activity makes the hyperpolarizing brake ineffective and leads BPH myocytes to a more contracted resting state.
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Affiliation(s)
- Sendoa Tajada
- Jose R. López-López: Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Edificio IBGM, c/ Sanz y Forés s/n, 47003 Valladolid, Spain.
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19
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20
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Harraz OF, Welsh DG. Protein kinase A regulation of T-type Ca2+ channels in rat cerebral arterial smooth muscle. J Cell Sci 2013; 126:2944-54. [PMID: 23613468 DOI: 10.1242/jcs.128363] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent investigations have identified that T-type Ca(2+) channels (CaV3.x) are expressed in rat cerebral arterial smooth muscle. In the study reported here, we isolated the T-type conductance, differentiated the current into the CaV3.1/CaV3.2 subtypes and determined whether they are subject to protein kinase regulation. Using patch clamp electrophysiology, whole-cell Ba(2+) current was monitored and initially subdivided into nifedipine-sensitive and -insensitive components. The latter conductance was abolished by T-type Ca(2+) channel blockers and was faster with leftward shifted activation/inactivation properties, reminiscent of a T-type channel. Approximately 60% of this T-type conductance was blocked by 50 µM Ni(2+), a concentration that selectively interferes with CaV3.2 channels. Subsequent work revealed that the whole-cell T-type conductance was subject to protein kinase A (PKA) modulation. Specifically, positive PKA modulators (db-cAMP, forskolin, isoproterenol) suppressed T-type currents and evoked a hyperpolarized shift in steady-state inactivation. Blocking PKA (with KT5720) masked this suppression without altering the basal T-type conductance. A similar effect was observed with stHt31, a peptide inhibitor of A-kinase anchoring proteins. A final set of experiments revealed that PKA-induced suppression targeted the CaV3.2 subtype. In summary, this study revealed that a T-type Ca(2+) channel conductance can be isolated in arterial smooth muscle, and differentiated into CaV3.1 and CaV3.2 components. It also showed that vasodilatory signaling cascades inhibit this conductance by targeting CaV3.2. Such targeting would impact Ca(2+) dynamics and consequent tone regulation in the cerebral circulation.
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Affiliation(s)
- Osama F Harraz
- Hotchkiss Brain and Libin Cardiovascular Research Institutes and Department of Physiology and Pharmacology, University of Calgary, AB, T2N 4N1, Canada
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21
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Shin WS, Oh S, An SW, Park GM, Kwon D, Ham J, Lee S, Park BG. 5E- and 5Z-farnesylacetones from Sargassum siliquastrum as novel selective L-type calcium channel blockers. Vascul Pharmacol 2013; 58:299-306. [PMID: 23416245 DOI: 10.1016/j.vph.2013.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 01/23/2013] [Accepted: 02/04/2013] [Indexed: 11/21/2022]
Abstract
A specific blocker of L-type Ca(2+) channels may be useful in decreasing arterial tone by reducing the open-state probability of L-type Ca(2+) channels. The aim of the present study was to evaluate the farnesylacetones, which are major active constituents of Sargassum siliquastrum, regarding their vasodilatation efficacies, selectivities toward L-type Ca(2+) channels, and in vivo antihypertensive activities. The application of 5E-(farnesylacetone 311) or 5Z-farnesylacetone (farnesylacetone 312) induced concentration-dependent vasodilatation effects on the basilar artery that was pre-contracted with depolarization and showed an ignorable potential role of endothelial-derived nitric oxide. We also tested farnesylacetone 311 or 312 to determine their pharmacological profiles for the blockade of native L-type Ca(2+) channels in basilar arterial smooth muscle cells (BASMCs) and ventricular myocytes (VMCs), cloned L- (α1C/β2a/α2δ), N- (α1B/β1b/α2δ), and T-type Ca(2+) channels (α1G, α1H, and α1I). Farnesylacetone 311 or 312 showed greater selectivity toward the L-type Ca(2+) channels among the tested voltage-gated Ca(2+) channels. The ranked order of the potency for farnesylacetone 311 was cloned α1C≒L-type (BASMC)≒L-type (VMCs)>α1B>α1H>α1I>α1G and that for farnesylacetone 312 was cloned α1C≒L-type (BASMCs)≒L-type (VMCs)>α1H>α1G>α1B>α1I. The oral administration of the farnesylacetone 311 (80mg/kg) conferred potent, long-lasting antihypertensive activity in spontaneous hypertensive rats, but it did not alter the heart rate.
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Affiliation(s)
- Woon-Seob Shin
- Department of Microbiology, College of Medicine, Kwandong University, Gangneung, 210-701, Republic of Korea
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22
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Joseph BK, Thakali KM, Moore CL, Rhee SW. Ion channel remodeling in vascular smooth muscle during hypertension: Implications for novel therapeutic approaches. Pharmacol Res 2013; 70:126-38. [PMID: 23376354 PMCID: PMC3607210 DOI: 10.1016/j.phrs.2013.01.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/10/2013] [Accepted: 01/17/2013] [Indexed: 02/07/2023]
Abstract
Ion channels are multimeric, transmembrane proteins that selectively mediate ion flux across the plasma membrane in a variety of cells including vascular smooth muscle cells (VSMCs). The dynamic interplay of Ca(2+) and K(+) channels on the plasma membrane of VSMCs plays a pivotal role in modulating the vascular tone of small arteries and arterioles. The abnormally-elevated arterial tone observed in hypertension thus points to an aberrant expression and function of Ca(2+) and K(+) channels in the VSMCs. In this short review, we focus on the three well-studied ion channels in VSMCs, namely the L-type Ca(2+) (CaV1.2) channels, the voltage-gated K(+) (KV) channels, and the large-conductance Ca(2+)-activated K(+) (BK) channels. First, we provide a brief overview on the physiological role of vascular CaV1.2, KV and BK channels in regulating arterial tone. Second, we discuss the current understanding of the expression changes and regulation of CaV1.2, KV and BK channels in the vasculature during hypertension. Third, based on available proof-of-concept studies, we describe the potential therapeutic approaches targeting these vascular ion channels in order to restore blood pressure to normotensive levels.
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Affiliation(s)
- Biny K Joseph
- Venenum Biodesign, 8 Black Forest Road, Hamilton, NJ 08691, USA
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23
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Ko EA, Wan J, Yamamura A, Zimnicka AM, Yamamura H, Yoo HY, Tang H, Smith KA, Sundivakkam PC, Zeifman A, Ayon RJ, Makino A, Yuan JXJ. Functional characterization of voltage-dependent Ca(2+) channels in mouse pulmonary arterial smooth muscle cells: divergent effect of ROS. Am J Physiol Cell Physiol 2013; 304:C1042-52. [PMID: 23426966 DOI: 10.1152/ajpcell.00304.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Electromechanical coupling via membrane depolarization-mediated activation of voltage-dependent Ca(2+) channels (VDCC) is an important mechanism in regulating pulmonary vascular tone, while mouse is an animal model often used to study pathogenic mechanisms of pulmonary vascular disease. The function of VDCC in mouse pulmonary artery (PA) smooth muscle cells (PASMC), however, has not been characterized, and their functional role in reactive oxygen species (ROS)-mediated regulation of vascular function remains unclear. In this study, we characterized the electrophysiological and pharmacological properties of VDCC in PASMC and the divergent effects of ROS produced by xanthine oxidase (XO) and hypoxanthine (HX) on VDCC in PA and mesenteric artery (MA). Our data show that removal of extracellular Ca(2+) or application of nifedipine, a dihydropyridine VDCC blocker, both significantly inhibited 80 mM K(+)-mediated PA contraction. In freshly dissociated PASMC, the maximum inward Ca(2+) currents were -2.6 ± 0.2 pA/pF at +10 mV (with a holding potential of -70 mV). Window currents were between -40 and +10 mV with a peak at -15.4 mV. Nifedipine inhibited currents with an IC(50) of 0.023 μM, and 1 μM Bay K8644, a dihydropyridine VDCC agonist, increased the inward currents by 61%. XO/HX attenuated 60 mM K(+)-mediated increase in cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)) due to Ca(2+) influx through VDCC in PASMC. Exposure to XO/HX caused relaxation in PA preconstricted by 80 mM K(+) but not in aorta and MA. In contrast, H(2)O(2) inhibited high K(+)-mediated increase in [Ca(2+)](cyt) and caused relaxation in both PA and MA. Indeed, RT-PCR and Western blot analysis revealed significantly lower expression of Ca(V)1.3 in MA compared with PA. Thus our study characterized the properties of VDCC and demonstrates that ROS differentially regulate vascular contraction by regulating VDCC in PA and systemic arteries.
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Affiliation(s)
- Eun A Ko
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
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24
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Li S, Maude-Griffin R, Pullan AJ, Chen JDZ. Gastric emptying and Ca(2+) and K(+) channels of circular smooth muscle cells in diet-induced obese prone and resistant rats. Obesity (Silver Spring) 2013; 21:326-35. [PMID: 23404843 DOI: 10.1002/oby.20021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Accepted: 06/18/2012] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Accelerated gastric emptying that precipitates hunger and frequent eating could be a potential factor in the development of obesity. The aim of this study was to study gastric emptying in diet-induced obese-prone (DIO-P) and DIO-resistant (DIO-R) rats and explore possible differences in electrical properties of calcium (Ca(2+) ) and potassium (K(+) ) channels of antral circular smooth muscle cells (SMCs). DESIGN AND METHODS Whole-cell patch-clamp technique was used to measure Ca(2+) and K(+) currents in single SMCs. Gastric emptying was evaluated 90 min after the ingestion of a solid meal. RESULTS Solid gastric emptying in the DIO-P rats was significantly faster compared with that in the DIO-R rats. The peak amplitude of L-type Ca(2+) current (IBa,L ) at 10 mV in DIO-P rats was greater than that in DIO-R rats without alternation of the current-voltage curve and voltage-dependent activation and inactivation. The half-maximal inactivation voltage of transient outward K(+) current (IKto ) was more depolarized (∼4 mV) in DIO-P rats compared with that in DIO-R rats. No difference was found in the current density or recovery kinetics of IKto between two groups. The current density of delayed rectifier K(+) current (IKdr ), which was sensitive to tetraethylammonium chloride but not 4-aminopyridine, was lower in DIO-P rats than that in DIO-R rats. CONCLUSION The accelerated gastric emptying in DIO-P rats might be attributed to a higher density of IBa,L , depolarizing shift of inactivation curve of IKto and lower density of IKdr observed in the antral SMCs of DIO-P rats.
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Affiliation(s)
- Shiying Li
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma, Oklahoma, USA
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25
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Pereira SL, Kummerle AE, Fraga CAM, Barreiro EJ, Sudo RT, Zapata-Sudo G. Vasodilator and antihypertensive effects of a novelN-acylhydrazone derivative mediated by the inhibition of L-type Ca2+channels. Fundam Clin Pharmacol 2012; 28:29-41. [DOI: 10.1111/j.1472-8206.2012.01076.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 06/25/2012] [Accepted: 08/07/2012] [Indexed: 11/29/2022]
Affiliation(s)
- Sharlene Lopes Pereira
- Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ 21941-590 Brazil
| | - Arthur Eugen Kummerle
- Instituto de Ciências Exatas, Universidade Federal Rural do Rio de Janeiro; Seropédica RJ 23890-000 Brazil
| | - Carlos Alberto Manssour Fraga
- Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ 21941-590 Brazil
- Programa de Pós-Graduação em Farmacologia e Química Medicinal, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ 21941-590 Brazil
| | - Eliezer Jesus Barreiro
- Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ 21941-590 Brazil
- Programa de Pós-Graduação em Farmacologia e Química Medicinal, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ 21941-590 Brazil
| | - Roberto Takashi Sudo
- Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ 21941-590 Brazil
- Programa de Pós-Graduação em Farmacologia e Química Medicinal, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ 21941-590 Brazil
| | - Gisele Zapata-Sudo
- Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ 21941-590 Brazil
- Programa de Pós-Graduação em Farmacologia e Química Medicinal, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ 21941-590 Brazil
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Lawton BK, Brown NJ, Reilly CS, Brookes ZLS. Role of L-type calcium channels in altered microvascular responses to propofol in hypertension. Br J Anaesth 2012; 108:929-35. [PMID: 22511481 DOI: 10.1093/bja/aes069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Anesthetics, Intravenous/pharmacology
- Animals
- Blood Pressure/drug effects
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/physiology
- Dose-Response Relationship, Drug
- Hypertension/physiopathology
- Male
- Microvessels/drug effects
- Microvessels/physiology
- Propofol/pharmacology
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Splanchnic Circulation/drug effects
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Affiliation(s)
- B K Lawton
- Microcirculation Research Group, Faculty of Medicine, Dentistry and Health, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
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27
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Pintérová M, Kuneš J, Zicha J. Altered neural and vascular mechanisms in hypertension. Physiol Res 2011; 60:381-402. [PMID: 21615201 DOI: 10.33549/physiolres.932189] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Essential hypertension is a multifactorial disorder which belongs to the main risk factors responsible for renal and cardiovascular complications. This review is focused on the experimental research of neural and vascular mechanisms involved in the high blood pressure control. The attention is paid to the abnormalities in the regulation of sympathetic nervous system activity and adrenoceptor alterations as well as the changes of membrane and intracellular processes in the vascular smooth muscle cells of spontaneously hypertensive rats. These abnormalities lead to increased vascular tone arising from altered regulation of calcium influx through L-VDCC channels, which has a crucial role for excitation-contraction coupling, as well as for so-called "calcium sensitization" mediated by the RhoA/Rho-kinase pathway. Regulation of both pathways is dependent on the complex interplay of various vasodilator and vasoconstrictor stimuli. Two major antagonistic players in the regulation of blood pressure, i.e. sympathetic nervous system (by stimulation of adrenoceptors coupled to stimulatory and inhibitory G proteins) and nitric oxide (by cGMP signaling pathway), elicit their actions via the control of calcium influx through L-VDCC. However, L-type calcium current can also be regulated by the changes in membrane potential elicited by the activation of potassium channels, the impaired function of which was detected in hypertensive animals. The dominant role of enhanced calcium influx in the pathogenesis of high blood pressure of genetically hypertensive animals is confirmed not only by therapeutic efficacy of calcium antagonists but especially by the absence of hypertension in animals in which L-type calcium current was diminished by pertussis toxin-induced inactivation of inhibitory G proteins. Although there is considerable information on the complex neural and vascular alterations in rats with established hypertension, the detailed description of their appearance during the induction of hypertension is still missing.
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Affiliation(s)
- M Pintérová
- Cardiovascular Research Center and Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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28
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Rhee SW, Stimers JR, Wang W, Pang L. Vascular smooth muscle-specific knockdown of the noncardiac form of the L-type calcium channel by microRNA-based short hairpin RNA as a potential antihypertensive therapy. J Pharmacol Exp Ther 2009; 329:775-82. [PMID: 19244098 DOI: 10.1124/jpet.108.148866] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In different rodent models of hypertension, vascular voltage-gated L-type calcium channel (Ca(L)) current and vascular tone is increased because of increased expression of the noncardiac form of the Ca(L) (Ca(v)1.2). The objective of this study was to develop a small interfering RNA (siRNA) expression system against the noncardiac form of Ca(v)1.2 to reduce its expression in vascular smooth muscle cells (VSMCs). siRNAs expressing plasmids and appropriate controls were constructed and first screened in human embryonic kidney (HEK) 293 cells cotransfected with a rat Ca(v)1.2 expression vector. The most effective gene silencing was achieved with a modified mir-30a-based short hairpin RNA (shRNAmir) driven by the cytomegalovirus promoter. In A7r5 cells, a vascular smooth muscle cell line, two copies of shRNAmir driven by a chimeric VSMC-specific enhancer/promoter reduced endogenous Ca(v)1.2 expression by 61% and decreased the Ca(L) current carried by barium by 47%. Moreover, the chimeric vascular smooth muscle-specific enhancer/promoter displayed almost no activity in non-VSMCs (PC-12 and HEK 293). Because the proposed siRNA was designed to only target the noncardiac form of Ca(v)1.2, it did not affect the Ca(L) expression and function in cultured cardiomyocytes, even when driven by a stronger cytomegalovirus promoter. In conclusion, vascular Ca(v)1.2 expression and function were effectively reduced by VSMC-specific delivery of the noncardiac form of Ca(v)1.2 siRNA without similarly affecting cardiac Ca(L) expression and function. When coupled with a viral vector, this molecular intervention in vivo may provide a novel long-term vascular-specific gene therapy for hypertension.
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Affiliation(s)
- Sung W Rhee
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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Belostotskaya GB, Zakharov EA, Klyueva NZ, Petrova EI, Nasledov GA. Some disturbances in the function of ryanodine receptors of spontaneously hypertensive rat cardiomyocytes detected using 4-chlorom-cresol. Biophysics (Nagoya-shi) 2008. [DOI: 10.1134/s0006350908060195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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The control of Ca2+ influx and NFATc3 signaling in arterial smooth muscle during hypertension. Proc Natl Acad Sci U S A 2008; 105:15623-8. [PMID: 18832165 DOI: 10.1073/pnas.0808759105] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many excitable cells express L-type Ca(2+) channels (LTCCs), which participate in physiological and pathophysiological processes ranging from memory, secretion, and contraction to epilepsy, heart failure, and hypertension. Clusters of LTCCs can operate in a PKCalpha-dependent, high open probability mode that generates sites of sustained Ca(2+) influx called "persistent Ca(2+) sparklets." Although increased LTCC activity is necessary for the development of vascular dysfunction during hypertension, the mechanisms leading to increased LTCC function are unclear. Here, we tested the hypothesis that increased PKCalpha and persistent Ca(2+) sparklet activity contributes to arterial dysfunction during hypertension. We found that PKCalpha and persistent Ca(2+) sparklet activity is indeed increased in arterial myocytes during hypertension. Furthermore, in human arterial myocytes, PKCalpha-dependent persistent Ca(2+) sparklets activated the prohypertensive calcineurin/NFATc3 signaling cascade. These events culminated in three hallmark signs of hypertension-associated vascular dysfunction: increased Ca(2+) entry, elevated arterial [Ca(2+)](i), and enhanced myogenic tone. Consistent with these observations, we show that PKCalpha ablation is protective against the development of angiotensin II-induced hypertension. These data support a model in which persistent Ca(2+) sparklets, PKCalpha, and calcineurin form a subcellular signaling triad controlling NFATc3-dependent gene expression, arterial function, and blood pressure. Because of the ubiquity of these proteins, this model may represent a general signaling pathway controlling gene expression and cellular function.
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A novel autoantibody in patients with primary hypertension: antibody against L-type Ca2+ channel. Chin Med J (Engl) 2008. [DOI: 10.1097/00029330-200808020-00003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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32
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Abstract
BACKGROUND This study was designed to test the hypothesis that differences exist in the inactivation properties of voltage-gated Ca(2+) channels (Ca(V)) in hypertensive arterial smooth muscle cells (ASMCs), and that these differences contribute to enhanced Ca(V) activity. METHODS The properties of Ca(V) were studied in freshly isolated myocytes from small mesenteric arteries (SMAs) of Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHRs) using whole-cell patch-clamp methods. RESULTS Peak currents (I(Ca)) were larger in SHR with either 2 mmol/l Ca(2+) or Ba(2+) as the charge carrier. In WKY and SHR, the peak current was larger with Ba(2+) than with Ca(2+) with no difference in their ratio. The voltage dependence of Ca(V) activation was shifted to the left in SHR as compared to WKY for Ca(2+) but not for Ba(2+), while availability was not different. The time course of inactivation of current could be represented by two time constants, both of which were larger in SHR than in WKY and also larger for Ba(2+) than for Ca(2+), with a greater fraction of inactivation being associated with the process slower in SHR and with Ba(2+). The time courses of availability, inactivation, and recovery from inactivation were faster in SHR than in WKY in the case of Ca(2+), but there was no difference in the case of Ba(2+). CONCLUSIONS These results demonstrate that there are differences between WKY and SHR in the inactivation properties of SMA Ca(V), and that these differences could contribute to larger steady-state currents. The differences cannot be explained merely by the presence of a larger number of identical Ca(V) complexes, and it appears likely that differences in intrinsic compositions, primary structures, and/or regulation are involved.
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Sonkusare S, Fraer M, Marsh JD, Rusch NJ. Disrupting calcium channel expression to lower blood pressure: new targeting of a well-known channel. Mol Interv 2007; 6:304-10. [PMID: 17200457 PMCID: PMC4917382 DOI: 10.1124/mi.6.6.3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Swapnil Sonkusare
- Department of Pharmacology & Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205-7199, USA.
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Xue JH, Zhang LF, Ma J, Xie MJ. Differential regulation of L-type Ca2+ channels in cerebral and mesenteric arteries after simulated microgravity in rats and its intervention by standing. Am J Physiol Heart Circ Physiol 2007; 293:H691-701. [PMID: 17351067 DOI: 10.1152/ajpheart.01229.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study was designed to clarify whether simulated microgravity can induce differential changes in the current and protein expression of the L-type Ca(2+) channel (Ca(L)) in cerebral and mesenteric arteries and whether these changes can be prevented by daily short-duration -G(x) exposure. Tail suspension [hindlimb unloading (HU)] for 3 and 28 days was used to simulate short- and medium-term microgravity-induced deconditioning effects. Standing (STD) for 1 h/day was used to provide -G(x) as a countermeasure. Whole cell patch-clamp experiments revealed an increase in current density of Ca(L) of vascular smooth muscle cells (VSMCs) isolated from cerebral arteries of rats subjected to HU and a decrease in VSMCs from mesenteric arteries. Western blot analysis revealed a significant increase and decrease of Ca(L) channel protein expression in cerebral and small mesenteric arterial VSMCs, respectively, only after 28 days of HU. STD for 1 h/day did not prevent the increase of Ca(L) current density in cerebral arterial VSMCs, but it prevented completely (within 3 days) and partially (28 days) the decrease of Ca(L) current density in small mesenteric arterial VSMCs. Consistent with the changes in Ca(L) current, STD for 1 h/day did not prevent the increase of Ca(L) expression in cerebrovascular myocytes but did prevent the reduction of Ca(L) expression in mesenteric arterial VSMCs subjected to 28 days of HU. These data indicate that simulated microgravity up- and downregulates the current and expression of Ca(L) in cerebral and hindquarter VSMCs, respectively. STD for 1 h/day differentially counteracted the changes of Ca(L) function and expression in cerebral and hindquarter arterial VSMCs of HU rats, suggesting the complexity of the underlying mechanisms in the effectiveness of intermittent artificial gravity for prevention of postflight cardiovascular deconditioning, which needs further clarification.
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Affiliation(s)
- Jun-Hui Xue
- Department of Aerospace Physiology, Fourth Military Medical University, Xi'an 710032, China
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Lewis SJ, Hashmi-Hill MP, Owen JR, Sandock K, Robertson TP, Bates JN. The vasodilator potency of the endothelium-derived relaxing factor, L-S-nitrosocysteine, is impaired in conscious spontaneously hypertensive rats. Vascul Pharmacol 2006; 44:476-90. [PMID: 16697269 DOI: 10.1016/j.vph.2006.03.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 02/20/2006] [Accepted: 03/23/2006] [Indexed: 02/07/2023]
Abstract
OBJECTIVE This study compared the hemodynamic responses elicited by the endothelium-derived relaxing factor (EDRF), L-S-nitrosocysteine (L-SNC), the non-prostanoid EDRF released by acetylcholine (ACh) and nitric oxide (NO)-donors such as MAHMA NONOate, in conscious spontaneously hypertensive (SH) and normotensive Wistar-Kyoto (WKY) rats. METHODS The depressor and/or vasodilator responses elicited by intravenous injections of ACh, L-SNC and MAHMA NONOate were determined in adult WKY and SH rats before and after intravenous injection of the NO synthesis inhibitor, N(G)-nitro-L-arginine methylester (L-NAME), or the cyclooxygenase inhibitor, indomethacin. RESULTS The responses elicited by ACh and L-SNC were smaller in SH than in WKY rats whereas the responses elicited by MAHMA NONOate were augmented in SH rats. The ACh-induced responses were not diminished after injection of L-NAME in WKY or SH rats. Indomethacin did not affect the responses to any of the vasodilator agents in WKY or SH rats. Addition of L-SNC to whole blood or thoracic aortae from SH rats yielded similar amounts of NO to those of WKY rats. CONCLUSIONS The vasodilator potencies of ACh and L-SNC were diminished whereas that of NO was augmented in SH rats. The loss of potency of L-SNC in SH rats was not obviously due to differences in decomposition to NO or the overactivity of cyclooxygenase factors. This study provides the first evidence that diminished endothelium-dependent vasodilation in SH rats may involve a loss of vasodilator potency of endogenous L-SNC.
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Affiliation(s)
- Stephen J Lewis
- Department of Physiology and Pharmacology, Institute of Comparative Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7389, USA.
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36
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Lewis SJ, Bhopatkar MY, Walton TM, Bates JN. Role of voltage-sensitive calcium-channels in nitric oxide-mediated vasodilation in spontaneously hypertensive rats. Eur J Pharmacol 2006; 528:144-9. [PMID: 16321377 DOI: 10.1016/j.ejphar.2005.10.056] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Revised: 10/25/2005] [Accepted: 10/28/2005] [Indexed: 11/22/2022]
Abstract
This study demonstrates that the vasodilator potencies of nitric oxide (NO) donors such as sodium nitroprusside are increased in conscious Spontaneously Hypertensive (SH) as compared to Wistar Kyoto (WKY) rats. For example, the NO donors do not dilate hindlimb resistance arteries in WKY rats whereas they elicit pronounced vasodilator responses in SH rats. This study also demonstrates that the NO-mediated vasodilator responses in WKY and SH rats were markedly diminished after blockade of voltage-sensitive Ca2+-channels (CaVS2+-channels) with nifedipine, diltiazem or verapamil. These findings suggest that NO dilates resistance arteries in vivo via direct and/or hyperpolarization-induced closure of CaVS2+-channels and that the increased potency of NO in SH rats may be due to the augmented CaVS2+-channel activity reported in this strain.
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Affiliation(s)
- Stephen J Lewis
- Department of Pharmacology and Physiology, University of Georgia, Athens, GA 30602-7389, USA.
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37
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Sonkusare S, Palade PT, Marsh JD, Telemaque S, Pesic A, Rusch NJ. Vascular calcium channels and high blood pressure: pathophysiology and therapeutic implications. Vascul Pharmacol 2006; 44:131-42. [PMID: 16427812 PMCID: PMC4917380 DOI: 10.1016/j.vph.2005.10.005] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Accepted: 10/05/2005] [Indexed: 10/25/2022]
Abstract
Long-lasting Ca(2+) (Ca(L)) channels of the Ca(v)1.2 gene family are heteromultimeric structures that are minimally composed of a pore-forming alpha(1C) subunit and regulatory beta and alpha(2)delta subunits in vascular smooth muscle cells. The Ca(L) channels are the primary pathways for voltage-gated Ca(2+) influx that trigger excitation-contraction coupling in small resistance vessels. Notably, vascular smooth muscle cells of hypertensive rats show an increased expression of Ca(L) channel alpha(1C) subunits, which is associated with elevated Ca(2+) influx and the development of abnormal arterial tone. Indeed, blood pressure per se appears to promote Ca(L) channel expression in small arteries, and even short-term rises in pressure may alter channel expression. Membrane depolarization has been shown to be one stimulus associated with elevated blood pressure that promotes Ca(L) channel expression at the plasma membrane. Future studies to define the molecular processes that regulate Ca(L) channel expression in vascular smooth muscle cells will provide a rational basis for designing antihypertensive therapies to normalize Ca(L) channel expression and the development of anomalous vascular tone in hypertensive pathologies.
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Affiliation(s)
- Swapnil Sonkusare
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, #611 Little Rock, AR 72205-7199, United States
| | - Philip T. Palade
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, #611 Little Rock, AR 72205-7199, United States
| | - James D. Marsh
- Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205-7199, United States
| | - Sabine Telemaque
- Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205-7199, United States
| | - Aleksandra Pesic
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, #611 Little Rock, AR 72205-7199, United States
| | - Nancy J. Rusch
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, #611 Little Rock, AR 72205-7199, United States
- Corresponding author. Tel.: +1 501 686 8038; fax: +1 501 686 5521. (N.J. Rusch)
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Xie MJ, Zhang LF, Ma J, Cheng HW. Functional alterations in cerebrovascular K+ and Ca2+ channels are comparable between simulated microgravity rat and SHR. Am J Physiol Heart Circ Physiol 2005; 289:H1265-76. [PMID: 15894580 DOI: 10.1152/ajpheart.00074.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exposure to microgravity leads to a sustained elevation in transmural pressure across the cerebral vasculature due to removal of hydrostatic pressure gradients. We hypothesized that ion channel remodeling in cerebral vascular smooth muscle cells (VSMCs) similar to that associated with hypertension may occur and play a role in upward autoregulation of cerebral vessels during microgravity. Sprague-Dawley rats were subjected to 4-wk tail suspension (Sus) to simulate the cardiovascular effect of microgravity. Large-conductance Ca2+-activated K+ (BKCa), voltage-gated K+ (KV), and L-type voltage-dependent Ca2+ (CaL) currents of Sus and control (Con) rat cerebral VSMCs were investigated with a whole cell voltage-clamp technique. Under the same experimental conditions, KV, BKCa, and CaL currents of cerebral VSMCs from adult spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were also investigated. KV current density decreased in Sus rats vs. Con rats [1.07 ± 0.14 ( n = 22) vs. 1.31 ± 0.28 ( n = 16) pA/pF at +20 mV ( P < 0.05)] and BKCa and CaL current densities increased [BKCa: 1.70 ± 0.37 ( n = 23) vs. 0.88 ± 0.22 ( n = 19) pA/pF at +20 mV ( P < 0.05); CaL: −2.17 ± 0.21 ( n = 35) vs. −1.31 ± 0.10 ( n = 26) pA/pF at +10 mV ( P < 0.05)]. Similar changes were also observed in SHR vs. WKY cerebral VSMCs: KV current density decreased [1.03 ± 0.33 ( n = 9) vs. 1.62 ± 0.64 ( n = 9) pA/pF at +20 mV ( P < 0.05)] and BKCa and CaL current densities increased [BKCa: 2.54 ± 0.47 ( n = 11) vs. 1.12 ± 0.33 ( n = 12) pA/pF at +20 mV ( P < 0.05); CaL: −3.99 ± 0.53 ( n = 12) vs. −2.28 ± 0.20 ( n = 10) pA/pF at +20 mV ( P < 0.05)]. These findings support our hypothesis, and their impact on space cardiovascular research is discussed.
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MESH Headings
- Animals
- Calcium/metabolism
- Calcium Channels, L-Type/physiology
- Cerebral Arteries/cytology
- Cerebral Arteries/physiology
- Disease Models, Animal
- Hypertension/physiopathology
- Large-Conductance Calcium-Activated Potassium Channels
- Male
- Membrane Potentials/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/physiology
- Patch-Clamp Techniques
- Potassium Channels, Calcium-Activated/physiology
- Potassium Channels, Voltage-Gated/physiology
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Rats, Sprague-Dawley
- Tail
- Weightlessness Simulation
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Affiliation(s)
- Man-Jiang Xie
- Department of Aerospace Physiology, Fourth Military Medical University, Xi'an 710032, China
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Vecchione C, Patrucco E, Marino G, Barberis L, Poulet R, Aretini A, Maffei A, Gentile MT, Storto M, Azzolino O, Brancaccio M, Colussi GL, Bettarini U, Altruda F, Silengo L, Tarone G, Wymann MP, Hirsch E, Lembo G. Protection from angiotensin II-mediated vasculotoxic and hypertensive response in mice lacking PI3Kgamma. ACTA ACUST UNITED AC 2005; 201:1217-28. [PMID: 15824082 PMCID: PMC2213159 DOI: 10.1084/jem.20040995] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hypertension affects nearly 20% of the population in Western countries and strongly increases the risk for cardiovascular diseases. In the pathogenesis of hypertension, the vasoactive peptide of the renin-angiotensin system, angiotensin II and its G protein–coupled receptors (GPCRs), play a crucial role by eliciting reactive oxygen species (ROS) and mediating vessel contractility. Here we show that mice lacking the GPCR-activated phosphoinositide 3-kinase (PI3K)γ are protected from hypertension that is induced by administration of angiotensin II in vivo. PI3Kγ was found to play a role in angiotensin II–evoked smooth muscle contraction in two crucial, distinct signaling pathways. In response to angiotensin II, PI3Kγ was required for the activation of Rac and the subsequent triggering of ROS production. Conversely, PI3Kγ was necessary to activate protein kinase B/Akt, which, in turn, enhanced L-type Ca2+ channel–mediated extracellular Ca2+ entry. These data indicate that PI3Kγ is a key transducer of the intracellular signals that are evoked by angiotensin II and suggest that blocking PI3Kγ function might be exploited to improve therapeutic intervention on hypertension.
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Affiliation(s)
- Carmine Vecchione
- Istituto di Ricovero e Cura a Carattere Scientifico, Neuromed, 86077 Pozzilli, Italy
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Tabet F, Savoia C, Schiffrin EL, Touyz RM. Differential Calcium Regulation by Hydrogen Peroxide and Superoxide in Vascular Smooth Muscle Cells from Spontaneously Hypertensive Rats. J Cardiovasc Pharmacol 2004; 44:200-8. [PMID: 15243301 DOI: 10.1097/00005344-200408000-00009] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We investigated the role of reactive oxygen species (ROS), particularly hydrogen peroxide (H2O2) and superoxide anion (*O2-) in the regulation of vascular smooth muscle cell (VSMC) Ca2+ concentration ([Ca2+]i) and vascular contraction and assessed whether redox-dependent Ca2+ signaling and contraction are altered in hypertension. VSMCs and mesenteric arteries from Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) were studied. Cells were stimulated with H2O2 (10(-4) mol/l) or LY83583 (*O2- generator, 10(-5) mol/l). [Ca2+]i and cytosolic *O2- were measured by fura-2AM and tempo-9-AC fluorescence respectively. L-type and T-type Ca2+ channels were assessed using verapamil/diltiazem and mibefradil respectively and mRNA and protein expression of these channels was assessed by real-time PCR and immunoblotting respectively. H2O2 time-dependently increased [Ca2+]i and contraction with significantly greater effects in SHR versus WKY (P < 0.001). LY83583 increased [Ca2+]i in both strains, but responses were blunted in SHR. Removal of extracellular Ca2+ abrogated [Ca2+]i responses to H2O2 and *O2-. Verapamil and diltiazem, but not mibefradil, significantly decreased H2O2 -induced [Ca2+]i responses with greater effects in SHR (P < 0.01). L-type and T-type Ca2+ channel inhibition reduced LY83583-mediated [Ca2+]i increase only in WKY cells. Both types of Ca2+ channels were expressed (mRNA and protein) in VSMCs from WKY and SHR, with greater abundance in SHR than WKY (2- to 3-fold). These results demonstrate that ROS increase vascular [Ca2+]i and contraction, primarily via extracellular Ca2+ influx. Whereas responses to H2O2 are enhanced, *O2- -mediated actions are blunted in SHR. These effects may relate to differential activation of Ca2+ channels by H2O2 and *O2-. Enhanced activation of L-type Ca2+ channels and increased Ca2+ influx by H2O2 may contribute to increased Ca2+ signaling in VSMCs from SHR.
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MESH Headings
- Aminoquinolines/metabolism
- Aminoquinolines/pharmacology
- Animals
- Calcium/metabolism
- Calcium Channels, L-Type/chemistry
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/genetics
- Calcium Channels, T-Type/chemistry
- Calcium Channels, T-Type/drug effects
- Calcium Channels, T-Type/genetics
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Diltiazem/pharmacology
- Dose-Response Relationship, Drug
- Hydrogen Peroxide/metabolism
- Male
- Mesenteric Arteries/cytology
- Mesenteric Arteries/drug effects
- Mibefradil/pharmacology
- Muscle Contraction/drug effects
- Muscle Contraction/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Reactive Oxygen Species/metabolism
- Superoxides/metabolism
- Verapamil/pharmacology
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Affiliation(s)
- Fatiha Tabet
- CIHR Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, University of Montreal, Quebec, Canada
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Abstract
T-type Ca2+ channels were originally called low-voltage-activated (LVA) channels because they can be activated by small depolarizations of the plasma membrane. In many neurons Ca2+ influx through LVA channels triggers low-threshold spikes, which in turn triggers a burst of action potentials mediated by Na+ channels. Burst firing is thought to play an important role in the synchronized activity of the thalamus observed in absence epilepsy, but may also underlie a wider range of thalamocortical dysrhythmias. In addition to a pacemaker role, Ca2+ entry via T-type channels can directly regulate intracellular Ca2+ concentrations, which is an important second messenger for a variety of cellular processes. Molecular cloning revealed the existence of three T-type channel genes. The deduced amino acid sequence shows a similar four-repeat structure to that found in high-voltage-activated (HVA) Ca2+ channels, and Na+ channels, indicating that they are evolutionarily related. Hence, the alpha1-subunits of T-type channels are now designated Cav3. Although mRNAs for all three Cav3 subtypes are expressed in brain, they vary in terms of their peripheral expression, with Cav3.2 showing the widest expression. The electrophysiological activities of recombinant Cav3 channels are very similar to native T-type currents and can be differentiated from HVA channels by their activation at lower voltages, faster inactivation, slower deactivation, and smaller conductance of Ba2+. The Cav3 subtypes can be differentiated by their kinetics and sensitivity to block by Ni2+. The goal of this review is to provide a comprehensive description of T-type currents, their distribution, regulation, pharmacology, and cloning.
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Affiliation(s)
- Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908-0735, USA.
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Fellner SK, Arendshorst WJ. Store-operated Ca2+ entry is exaggerated in fresh preglomerular vascular smooth muscle cells of SHR. Kidney Int 2002; 61:2132-41. [PMID: 12028453 DOI: 10.1046/j.1523-1755.2002.00383.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Regulation of preglomerular vasomotor tone vessels ultimately control glomerular filtration rate, sodium reabsorption and systemic blood pressure. To gain insight into the complex renal hemodynamic factors that may result in hypertension, we studied calcium signaling pathways. METHODS Fresh, single, preglomerular vascular smooth muscle cells (VSMC) were isolated from 5- to 6-week-old SHR and WKY utilizing a magnetized microsphere/sieving technique. Cytosolic Ca2+ ([Ca2+]i) was measured with fura-2 ratiometric fluorescence. To examine store-operated calcium entry (SOC), VSMC were activated in calcium-free buffer containing nifedipine. To deplete the sarcoplasmic reticulum (SR) of Ca2+, vasopressin-1 receptor agonist [V1R; inositol trisphosphate (IP3)-mediated mobilization], ryanodine (non-IP3 induced mobilization), and cyclopiazonic acid (CPA; Ca2+-ATPase inhibition) were utilized. Addition of external calcium followed by quenching of the fura/Ca2+ signal with Mn2+ permitted assessment of divalent cation entry via SOC. RESULTS V1R caused greater mobilization in SHR than WKY (P < 0.01) as well as greater calcium entry (P < 0.001). Ryanodine and CPA both caused SR calcium depletion that was not statistically different between strains, but absolute calcium entry through SOC was more than double in SHR following either maneuver (P < 0.001). 2-Amino-ethoxybiphenyl borane (2-APB), an inhibitor not only of IP3 receptors, but also of SOC, blocked calcium entry in the ryanodine and CPA experiments independent of IP3. As well, Gd3+, a selective inhibitor of SOC, inhibited the Ca2+ response. We also studied L-channel calcium entry stimulated by V1R. The total calcium response was greater in SHR as was the absolute inhibition by nifedipine. As a percent of the total response, participation of L-type channels sensitive to nifedipine was about 45% in both strains of rat. CONCLUSION Utilizing three separate mechanisms to deplete the SR of Ca2+ in order to activate SOC, we show for the first time, that SOC is exaggerated in preglomerular VSMC of young SHR.
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MESH Headings
- Animals
- Animals, Newborn/metabolism
- Arginine Vasopressin/pharmacology
- Arterioles
- Calcium/metabolism
- Calcium Channels/drug effects
- Calcium Channels/metabolism
- Calcium Channels, L-Type/metabolism
- Calcium-Transporting ATPases/antagonists & inhibitors
- Indoles/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors
- Kidney Glomerulus/blood supply
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Protein Isoforms/metabolism
- Rats
- Rats, Inbred SHR/metabolism
- Rats, Inbred WKY
- Receptors, Cytoplasmic and Nuclear/drug effects
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Vasopressin/agonists
- Ryanodine/pharmacology
- Ryanodine Receptor Calcium Release Channel/drug effects
- Ryanodine Receptor Calcium Release Channel/metabolism
- Sarcoplasmic Reticulum/enzymology
- Vasopressins/metabolism
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Affiliation(s)
- Susan K Fellner
- Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, 27599-7545, USA.
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43
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Dobesová Z, Kunes J, Zicha J. The altered balance between sympathetic nervous system and nitric oxide in salt hypertensive Dahl rats: ontogenetic and F2 hybrid studies. J Hypertens 2002; 20:945-55. [PMID: 12011656 DOI: 10.1097/00004872-200205000-00030] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE We have demonstrated earlier that the nitric oxide (NO) system is not able to counterbalance effectively the hyperactivity of the sympathetic nervous system (SNS) in salt hypertension of young Dahl rats in which augmented superoxide anion formation lowers NO bioavailability. The aim of the present study was to determine whether SNS hyperactivity and/or relative NO deficiency are also present in salt hypertension elicited in adult Dahl rats, and whether they are associated with blood pressure (BP) in the F2 population of Dahl rats. DESIGN AND METHODS The contribution of major vasoactive systems [renin-angiotensin system (RAS), SNS and NO] and superoxide anions to BP maintenance was studied in SS/Jr rats in which salt hypertension was induced either in adulthood or in youth (8% NaCl diet from the age of 12 or 4 weeks). The contribution of particular vasoactive systems was also investigated in 122 young salt-loaded F2hybrids [derived from salt-sensitive (SS/Jr) and salt-resistant (SR/Jr) Dahl rats] which were fed a high-salt diet (8% NaCl) for 6 weeks after weaning. Mean arterial pressure (MAP) was measured in conscious animals subjected to acute consecutive blockade of RAS (captopril 10 mg/kg i.v.), SNS (pentolinium 5 mg/kg i.v.) and NO synthase (l-NAME 30 mg/kg i.v.). RESULTS Dahl rats with salt hypertension induced in adulthood were also characterized by enhanced pentolinium-induced BP fall (DeltaMAPpento), but their residual BP (recorded after the blockade of both RAS and SNS) was unaltered, in contrast to its elevation seen in young salt-hypertensive rats. The BP rise after NO synthase inhibition by l-NAME (DeltaMAPL-NAME), which was substantially greater in adult than in young hypertensive rats, was not enhanced by superoxide scavenging with tempol in adult hypertensive animals, in which this drug elicited a moderate BP reduction only. Basal MAP of young salt-loaded F2 hybrids was positively associated not only with DeltaMAPpento (P < 0.0001) and residual BP (P < 0.001) but also with DeltaMAPL-NAME (P < 0.001). The slope of the relationship between basal BP and pentolinium-induced BP changes was steeper than that between basal BP and BP changes elicited by l-NAME. The positive correlation of basal BP with DeltaMAPpento/DeltaMAPL-NAME ratio (P < 0.01) indicates that an altered balance between sympathetic vasoconstriction and NO-dependent vasodilation was associated with high blood pressure, even in the F2 population of Dahl rats. CONCLUSIONS A comparison of young and adult salt-hypertensive Dahl rats stressed the importance of increased residual BP and relative NO deficiency for the severity of hypertension, because these two alterations were absent in a less-pronounced form of salt hypertension elicited in adulthood. The findings obtained in our young salt-loaded F2 population also confirm the major importance of both sympathetic hyperactivity and relative NO deficiency for the maintenance of salt hypertension in Dahl rats.
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Affiliation(s)
- Zdena Dobesová
- Institute of Physiology, Academy of Sciences of the Czech Republic, and Center for Experimental Research of Cardiovascular Diseases, Prague, Czech Republic
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44
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Shimamura K, Zhou M, Ito Y, Kimura S, Zou LB, Sekiguchi F, Kitramura K, Sunano S. Effects of flufenamic acid on smooth muscle of the carotid artery isolated from spontaneously hypertensive rats. J Smooth Muscle Res 2002; 38:39-50. [PMID: 12199531 DOI: 10.1540/jsmr.38.39] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Endothelium-removed carotid artery strips from stroke-prone spontaneously hypertensive rats spontaneously developed a tonic myogenic contraction. Flufenamic acid reduced the resting tone observed during superfusion with Tyrode's solution, in a concentration-dependent manner. Flufenamic acid also inhibited contractions produced by high-K solutions in a concentration-dependent manner. The resting membrane potential of smooth muscle cells in the artery was around -32 mV, with occasional oscillatory potentials. Flufenamic acid hyperpolarized the membrane in a concentration-dependent manner. The voltage-dependent outward currents recorded in isolated cells with micropipettes filled with high-K+ solution (holding potential, -60 mV) were enhanced by flufenamic acid and inhibited by tetraethylammonium. When the recording micropipette was filled with high Cs to inhibit the K+-current, depolarizing step pulses evoked nifedipine-sensitive inward currents. Flufenamic acid inhibited the inward currents. These results indicate that flufenamic acid inhibits the spontaneous active tone of the carotid artery by inhibiting L-type Ca2+-channels and possibly by membrane hyperpolarization through activation of the voltage-dependent K+-channels.
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MESH Headings
- Animals
- Anti-Inflammatory Agents, Non-Steroidal/pharmacology
- Calcium/metabolism
- Calcium Channels, L-Type/physiology
- Carotid Artery, Common/drug effects
- Carotid Artery, Common/physiology
- Flufenamic Acid/pharmacology
- Male
- Membrane Potentials/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Patch-Clamp Techniques
- Potassium/metabolism
- Potassium Channels, Voltage-Gated/physiology
- Rats
- Rats, Inbred SHR
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Affiliation(s)
- Keiichi Shimamura
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Japan.
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45
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Asano M, Nomura Y. Contribution of sarcoplasmic reticulum Ca2+ to the activation of Ca2+ -activated K+ channels in the resting state of arteries from spontaneously hypertensive rats. J Hypertens 2002; 20:447-54. [PMID: 11875312 DOI: 10.1097/00004872-200203000-00020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Localized release of Ca2+ from the sarcoplasmic reticulum (SR) toward the plasmalemma, sometimes visualized as Ca2+ sparks, can activate Ca2+-activated K+ (KCa) channels. We have already reported that the addition of charybdotoxin (ChTX), a blocker of KCa channels, to the resting state of arteries from spontaneously hypertensive rats (SHR) caused a powerful contraction, suggesting that KCa channels were active in the resting state. This study aimed to determine whether the Ca2+ responsible for activity of KCa channels was derived from SR. METHODS Possible mechanisms underlying the ChTX-induced contractions were examined in endothelium-denuded strips of femoral, mesenteric, small mesenteric and carotid arteries from 13-week-old SHR and normotensive Wistar-Kyoto (WKY) rats by using selective inhibitors of the Ca2+ spark process. RESULTS ChTX (100 nmol/l) induced a contraction in the SHR arteries. The ChTX-induced contractions were increased by a moderate membrane depolarization by 15.9 mmol/l K+ and were abolished by nifedipine (100 nmol/l). When SR Ca2+ was depleted by treatment of the strips with ryanodine (10 mumol/l) plus caffeine (20 mmol/l) or with thapsigargin (100 nmol/l), the ChTX-induced contraction was decreased in femoral, mesenteric and small mesenteric arteries and was almost abolished in the carotid artery. A similar phenomenon can be observed in arteries from WKY rats after a moderate membrane depolarization. In both SHR and WKY rats, SR Ca2+-dependent ChTX-induced contraction always represents 20-30% of the maximal K+-induced contraction. CONCLUSIONS We conclude that activation of KCa channels depended upon influx of Ca2+ through L-type Ca2+ channels and release of Ca2+ from the SR, suggesting that recycling of entering Ca2+ from the superficial SR toward the plasmalemma sufficiently elevated Ca2+ near these channels to activate them.
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Affiliation(s)
- Masahisa Asano
- Department of Pharmacology, Nagoya City University Medical School, Nagoya, Japan.
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46
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Nomura Y, Asano M. Increased Ca2+ buffering function of sarcoplasmic reticulum in small mesenteric arteries from spontaneously hypertensive rats. Hypertens Res 2002; 25:231-9. [PMID: 12047039 DOI: 10.1291/hypres.25.231] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We compared the Ca2+ buffering function of the superficial sarcoplasmic reticulum (SR) during rest and during contraction in endothelium-denuded strips of small mesenteric arteries from 13-week-old spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). The addition of caffeine (1-20 mM) caused a transient contraction in both strains, and the contraction was significantly larger in SHR. When the SR Ca2+ buffering function was eliminated by cyclopiazonic acid (CPA; 10 microM) or thapsigargin (100 nM), both of which inhibit SR Ca2+-ATPase, or by ryanodine (10 microM), which depletes the SR Ca2+, there was a larger contraction in SHR than in WKY, suggesting that the Ca2+ buffering function of the SR during rest is more important in SHR than in WKY. Judging from the augmenting effects of these three agents on the contractile responses to Bay k 8644 (1-300 nM), an agonist of L-type Ca2+ channels, or norepinephrine (10(-9)-10(-4) M), an alpha-adrenoceptor agonist, the effects were significantly greater in SHR than in WKY. We conclude that 1) the Ca2+ influx during rest and during stimulation with Bay k 8644 or norepinephrine is strongly buffered by Ca2+ uptake into the superficial SR in the small mesenteric arteries from SHR and WKY; and 2) these Ca2+ buffering functions are increased in SHR because of the larger capacity of SR for Ca2+ storage.
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Affiliation(s)
- Yukiko Nomura
- Department of Pharmacology, Nagoya City University Medical School, Nagoya, Japan
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47
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Li B, Chik CL, Ho AK, Karpinski E. L-type Ca(2+) channel regulation by pituitary adenylate cyclase-activating polypeptide in vascular myocytes from spontaneously hypertensive rats. Endocrinology 2001; 142:2865-73. [PMID: 11416005 DOI: 10.1210/endo.142.7.8229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP), a vasoactive peptide, modulates the L-type Ca(2+) channel current (L channel current) in vascular smooth muscle cells (VSMC) through activation and integration of two intracellular pathways, protein kinase A and protein kinase C (PKC). In the present study we compared the effects of PACAP on the L channel current in VSMC from the spontaneously hypertensive rats (SHR) and normotensive controls, Wistar Kyoto rats (WKY). We found that compared with WKY, VSMC from SHR had a higher L channel current density. Stimulation by PACAP (10 nM) caused an increase in the amplitude of the whole cell current and prolonged open time in VSMC from SHR and WKY, with the increase greater in SHR. These effects of PACAP on the L channel current was mimicked by an activator of PKC. In contrast, PACAP caused a smaller increase in cAMP accumulation in VSMC from SHR than WKY, and there was no difference in the inhibitory effect of 8-bromo-cAMP on the L channel current from both type of cells. The greater increase in amplitude of the L channel current by PACAP in VSMC from SHR persisted in the presence of adenosine cyclic 3',5'-monophosphothioate, Rp-isomer, a cAMP antagonist, but not calphostin C, a PKC inhibitor. Taken together, our results show an increase in L channel current density and an enhanced PACAP effect on the L channel current in VSMC from SHR compared with WKY. This difference in PACAP response appears to be predominately secondary to an increased PKC sensitivity.
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MESH Headings
- Animals
- Arteries
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/physiology
- Cyclic AMP-Dependent Protein Kinases/physiology
- Electric Conductivity
- Hypertension/physiopathology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Neuropeptides/pharmacology
- Neuropeptides/physiology
- Pituitary Adenylate Cyclase-Activating Polypeptide
- Protein Kinase C/physiology
- Rats
- Rats, Inbred SHR/physiology
- Rats, Inbred WKY
- Reference Values
- Tail/blood supply
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Affiliation(s)
- B Li
- Departments of Physiology and Medicine, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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48
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Eto K, Ohya Y, Nakamura Y, Abe I, Fujishima M. Comparative actions of insulin sensitizers on ion channels in vascular smooth muscle. Eur J Pharmacol 2001; 423:1-7. [PMID: 11438300 DOI: 10.1016/s0014-2999(01)01047-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Thiazolidinedione and isoxazolidinedione insulin sensitizers activate peroxisome proliferator-activated receptor gamma (PPAR gamma). Some thiazolidinediones modify ion channels in smooth muscles; however, the mechanism by which their actions occur has not been clarified. We, thus, examined the effects of three thiazolidinediones (troglitazone, pioglitazone, and rosiglitazone) and isoxazolidinedione (JTT-501), as well as an intrinsic ligand for PPAR gamma, 15-deoxy-Delta(12,14) prostaglandin J(2) (prostaglandin J(2)), on voltage-operated Ca(2+) currents (I(Ca)), voltage-dependent K(+) currents (I(Kv)), and Ca(2+)-activated K(+) currents (I(Kca)), to clarify whether a thiazolidinedione structure or PPAR gamma activation is related to their actions on ion channels. The whole-cell patch clamp method was used to record currents in smooth muscle cells from guinea-pig mesenteric arteries. Thiazolidinediones inhibited I(Ca) in a dose-dependent manner (troglitazone>pioglitazone=rosiglitazone). Troglitazone (> or =1 microM) and rosiglitazone (100 microM), but not pioglitazone, inhibited I(Kv). Rosiglitazone (> or =10 microM) enhanced, troglitazone (> or =1 microM) inhibited, and pioglitazone did not affect I(Kca). A high concentration of JTT-501 (100 microM) inhibited I(Ca), I(Kv), and I(Kca) to a similar extent. Prostaglandin J(2) enhanced I(Kca), but affected neither I(Ca) nor I(Kv). In summary, the three thiazolidinediones and isoxazolidinedione act differently on Ca(2+) and K(+) channels in vascular smooth muscle. The action of thiazolidinediones on I(Ca) could be attributed to specific regions of the molecules and not to activation of PPAR gamma. Involvement of PPAR gamma activation in the stimulation of I(Kca) is possible but should be tested further.
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Affiliation(s)
- K Eto
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi, Fukuoka 812-8582, Japan
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49
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Rapacon-Baker M, Zhang F, Pucci ML, Guan H, Nasjletti A. Expression of myogenic constrictor tone in the aorta of hypertensive rats. Am J Physiol Regul Integr Comp Physiol 2001; 280:R968-75. [PMID: 11247816 DOI: 10.1152/ajpregu.2001.280.4.r968] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the effect of intraluminal pressure or stretch on the development of tone in the descending thoracic aorta from rats with aortic coarctation-induced hypertension of 7-14 days duration. Increments of pressure >100 mmHg decreased the diameter of thoracic aortas from hypertensive but not from normotensive rats. The pressure-induced constriction was not demonstrable in vessels superfused with calcium-free buffer. Stretched rings of aorta from hypertensive rats exhibited a calcium-dependent constrictor tone accompanied by elevated calcium influx that varied in relation to the degree of stretch. Blockers of L-type calcium channels and inhibitors of protein kinase C reduced both basal tone and calcium influx in aortic rings of hypertensive rats. Hence, the thoracic aorta of hypertensive rats expresses a pressure- and stretch-activated constrictor mechanism that relies on increased calcium influx through L-type calcium channels via a protein kinase C-regulated pathway. The expression of such a constrictor mechanism is suggestive of acquired myogenic behavior.
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MESH Headings
- Animals
- Aorta, Abdominal/physiology
- Aorta, Abdominal/physiopathology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Aorta, Thoracic/physiopathology
- Aortic Coarctation/physiopathology
- Calcium/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/physiology
- Enzyme Inhibitors/pharmacology
- Gadolinium/pharmacology
- In Vitro Techniques
- Isometric Contraction/drug effects
- Isometric Contraction/physiology
- Male
- Muscle Tonus/drug effects
- Muscle Tonus/physiology
- Muscle, Smooth, Vascular/physiology
- Muscle, Smooth, Vascular/physiopathology
- Nifedipine/pharmacology
- Protein Kinase C/antagonists & inhibitors
- Rats
- Rats, Inbred Strains
- Staurosporine/pharmacology
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
- Verapamil/pharmacology
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Affiliation(s)
- M Rapacon-Baker
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595, USA
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50
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Nakamura Y, Ohya Y, Abe I, Fujishima M. Sodium-potassium pump current in smooth muscle cells from mesenteric resistance arteries of the guinea-pig. J Physiol 1999; 519 Pt 1:203-12. [PMID: 10432351 PMCID: PMC2269488 DOI: 10.1111/j.1469-7793.1999.0203o.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
1. The Na+-K+ pump current was studied in smooth muscle cells from mesenteric resistance arteries of guinea-pigs by the use of the perforated patch-clamp technique in the presence of blockers for various ion channels and exchangers. 2. When the Na+ concentration in the pipette solution ([Na+]i) was 50 mM, an increase in the extracellular K+ concentration ([K+]o) from 0 to 10 mM caused an outward current. Both the removal of K+ from the bath solution and the application of 10 microM ouabain abolished this current. Thus, this K+-induced and ouabain-sensitive current was considered to be the Na+-K+ pump current. 3. The amplitude of the Na+-K+ pump current increased as the membrane potential was made more positive until around 0 mV, while the amplitude saturated at more positive potentials than 0 mV. 4. An increase in [K+]o or [Na+]i amplified the Na+-K+ pump current. For [K+]o, the binding constant (Kd) was 1.6+/-0.3 mM and the Hill coefficient (nH) was 1.1+/-0.2 (n = 6). For [Na+]i, Kd was 22+/-5 mM and nH was 1.7+/-0.5 (n = 4-19). 5. The presence of various monovalent cations other than Na+ in the bath solution also evoked the Na+-K+ pump current. The order of potency was K+ >= Rb+ > Cs+ >> Li+. 6. Ouabain inhibited the Na+-K+ pump current in a dose-dependent manner with a Kd of 0.35+/-0.03 microM and an nH of 1.2+/-0.1 (n = 6-8). 7. The Na+-K+ pump current increased as temperature increased. The temperature coefficient (Q10; 26-36 C) was 1.87 (n = 9). 8. In summary the present study characterized for the first time the Na+-K+ pump current in vascular smooth muscle cells by the use of the voltage-clamp method. The use of this method should provide essential information for Na+,K+-ATPase-mediated changes in the cell functions of vascular smooth muscle cells.
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Affiliation(s)
- Y Nakamura
- Second Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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