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Pannangpetch P, Tangsucharit P, Thanaruksa R, Proongkhong T, Srisuwan S, Aekthammarat D. Antihypertensive effect of Mali-Nil surin rice bran hydrolysate and its mechanisms related to the EDHF-mediated vasorelaxation and L-type Ca 2+ channel-mediated vasoconstriction in L-NAME hypertensive rats. Biomed Pharmacother 2022; 150:113003. [PMID: 35462340 DOI: 10.1016/j.biopha.2022.113003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/12/2022] [Accepted: 04/17/2022] [Indexed: 11/29/2022] Open
Abstract
Mali-Nil Surin rice bran hydrolysate (MRH) contains highly nutritional proteins and beneficial phenolic compounds. This study investigated an antihypertensive effect of MRH and evaluated the mechanisms mediating this action in Nω-nitro-L-arginine-methyl ester (L-NAME)-induced hypertensive rats. Antihypertensive activity was determined in male rats orally administered with MRH (100 or 300 mg/kg) or enalapril (15 mg/kg) daily together with L-NAME (50 mg/kg/day) in drinking water, for 21 days. Concurrent oral treatment with MRH lowered the high blood pressure in the L-NAME-induced hypertensive rats. MRH treatment improved endothelial function and increased the endothelium-derived hyperpolarizing factor-mediated vasorelaxation in L-NAME hypertensive rats. L-NAME rats treated with MRH had reduced adrenergic hypercontractility, which was associated with a decrease in L-type calcium channel-mediated vasoconstriction. In addition, MRH exhibited antioxidant activity in hypertensive rats, as indicated by suppression of vascular superoxide anion production and reduction of malondialdehyde levels, as well as magnification of superoxide dismutase and catalase activities in serum. This study demonstrated the nutraceutical potential of MRH to prevent oxidative stress-related vascular dysfunction in hypertension.
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Affiliation(s)
- Patchareewan Pannangpetch
- Cardiovascular Research Group, Khon Kaen University, Khon Kaen 40002, Thailand; Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Panot Tangsucharit
- Cardiovascular Research Group, Khon Kaen University, Khon Kaen 40002, Thailand; Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | | | | | - Supawadee Srisuwan
- Department of Basic Medical Science, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok 10300, Thailand
| | - Direk Aekthammarat
- Department of Basic Medical Science, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok 10300, Thailand.
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Functional, electrophysiology, and molecular dynamics analysis of quercetin-induced contraction of rat vascular musculature. Eur J Pharmacol 2022; 918:174778. [DOI: 10.1016/j.ejphar.2022.174778] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/14/2022] [Accepted: 01/24/2022] [Indexed: 12/21/2022]
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GSK-7975A, an inhibitor of Ca 2+ release-activated calcium channels, depresses isometric contraction of mouse aorta. Eur J Pharmacol 2021; 906:174197. [PMID: 34052216 DOI: 10.1016/j.ejphar.2021.174197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/28/2021] [Accepted: 05/17/2021] [Indexed: 11/21/2022]
Abstract
GSK-7975A is described to inhibit stromal interaction molecule 1(STIM1)-mediated Ca2+ release-activated Ca2+ channels ORAI 1, ORAI 2 and ORAI 3 in different cell types. The present study investigated whether isometric contractions of mouse aortic segments were affected by this selective store-operated calcium channel inhibitor. Depending on the way by which Ca2+ influx pathways were activated during contraction, GSK-7975A inhibited contractility of mouse aortic segments with different affinity. When contractile effects were induced by depolarization as with elevated extracellular K+ and opening of voltage-gated calcium channels, the affinity was approximately 10 times lower than when contraction was elicited with Ca2+ influx via non-selective cation channels. GSK-7975A may repolarize the aortic smooth muscle cells by inhibiting non-selective cation channels, has no effect on IP3-mediated phenylephrine-induced phasic contractions or on refilling of the contractile sarcoplasmic reticulum Ca2+ store, but has significant effects on non-contractile store-operated Ca2+ influx.
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Ren LS, Zhang L, Zhu D, Li T, Wang Q, Yuan XY, Hao LR. KMUP-1 regulates the vascular calcification in chronic renal failure by mediating NO/cGMP/PKG signaling pathway. Life Sci 2020; 253:117683. [PMID: 32315727 DOI: 10.1016/j.lfs.2020.117683] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/15/2020] [Accepted: 04/15/2020] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To explore the potential mechanism of KMUP-1 in the vascular calcification of chronic renal failure (CRF) through mediating NO/cGMP/PKG pathway, and provide novel insights into the CRF treatment. METHODS CRF rats were treated by KMUP-1 with/without L-NNA (a NOS inhibitor) and then performed by ELISA, alizarin red staining, Von Kossa staining, Masson's trichrome, Sirius red staining and CD3 immunohistochemical staining. Simultaneously, vascular smooth muscle cells (VSMCs) were collected from rats to confirm the effect of KMUP-1 on vascular calcification in vitro via NO/cGMP/PKG pathway. Besides, protein and mRNA expressions were determined via Western blotting and qRT-PCR, respectively. RESULTS CRF rats were elevated in 24-h urine protein, blood urea nitrogen (BUN), serum creatinine, Cys-C levels and inflammatory cytokines. Besides, CRF rats also showed increased calcium content and ALP level with up-regulated mRNA of osteogenic differentiation-related markers. Furthermore, the up-regulated expressions of eNOS and PKG, as well as down-regulated levels of NOx and cGMP were also found in CRF rats. However, renal failure and vascular calcification of CRF were improved significantly by KMUP-1 treatment via activation of NO/cGMP/PKG pathway. Moreover, KMUP-1 treatment attenuated calcified VSMCs, accompanied by the decreases in the calcified nodules, level of calcium and activity of ALP. In addition, either L-NNA treatment for CRF rats or the calcified VSMCs could antagonize the improving effect of KMUP-1. CONCLUSION KMUP-1 can improve the renal function and vascular calcification in CRF rats at least in part by activating NO/cGMP/PKG pathway.
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Affiliation(s)
- Lian-Sheng Ren
- Department of Nephrology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Lei Zhang
- Department of Nephrology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Dan Zhu
- Department of Nephrology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Tong Li
- Department of Nephrology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Qi Wang
- Department of Nephrology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Xue-Ying Yuan
- Department of Nephrology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Li-Rong Hao
- Department of Nephrology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China.
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5
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Fardoun M, Dehaini H, Shaito A, Mesmar J, El-Yazbi A, Badran A, Beydoun E, Eid AH. The hypertensive potential of estrogen: An untold story. Vascul Pharmacol 2019; 124:106600. [PMID: 31629918 DOI: 10.1016/j.vph.2019.106600] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/18/2019] [Accepted: 09/25/2019] [Indexed: 12/24/2022]
Abstract
Cardiovascular disease (CVD) is the major cause of morbidity and mortality worldwide. The implication of estrogen in this disease has been extensively studied. While the vast majority of published research argue for a cardioprotective role of estrogen in vascular inflammation such as in atherosclerosis, the role of estrogen in hypertension remains far from being resolved. The vasorelaxant effect of estrogen has already been well-established. However, emerging evidence supports a vasoconstrictive potential of this hormone. It has been proposed that the microenvironment dictates the effect of estrogen-induced type 1 nitric oxide synthase-1 (nNOS) on vasotone. Indeed, depending on nNOS product, nitric oxide or superoxide, estrogen can induce vasodilation or vasoconstriction, respectively. In this review, we discuss the evidence supporting the vasorelaxant effects of estrogen, and the molecular players involved. Furthermore, we shed light on recent reports revealing a vasoconstrictive role of estrogen, and speculate on the underlying signaling pathways. In addition, we identify certain factors that can account for the discrepant estrogenic effects. This review emphasizes a yin-yang role of estrogen in regulating blood pressure.
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Affiliation(s)
- Manal Fardoun
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Hassan Dehaini
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, Lebanon
| | - Abdallah Shaito
- Department of Biological and Chemical Sciences, Faculty of Arts and Sciences, Lebanese International University, 1105 Beirut, Lebanon
| | - Joelle Mesmar
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Ahmed El-Yazbi
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, Lebanon; Department of Pharmacology and Toxicology, Alexandria University, Alexandria, Egypt
| | - Adnan Badran
- Department of Nutrition, University of Petra, Amman, Jordan
| | - Elias Beydoun
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Ali H Eid
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, Lebanon; Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar.
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Jensen LJ, Nielsen MS, Salomonsson M, Sørensen CM. T-type Ca 2+ channels and autoregulation of local blood flow. Channels (Austin) 2017; 11:183-195. [PMID: 28055302 DOI: 10.1080/19336950.2016.1273997] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
L-type voltage gated Ca2+ channels are considered to be the primary source of calcium influx during the myogenic response. However, many vascular beds also express T-type voltage gated Ca2+ channels. Recent studies suggest that these channels may also play a role in autoregulation. At low pressures (40-80 mmHg) T-type channels affect myogenic responses in cerebral and mesenteric vascular beds. T-type channels also seem to be involved in skeletal muscle autoregulation. This review discusses the expression and role of T-type voltage gated Ca2+ channels in the autoregulation of several different vascular beds. Lack of specific pharmacological inhibitors has been a huge challenge in the field. Now the research has been strengthened by genetically modified models such as mice lacking expression of T-type voltage gated Ca2+ channels (CaV3.1 and CaV3.2). Hopefully, these new tools will help further elucidate the role of voltage gated T-type Ca2+ channels in autoregulation and vascular function.
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Affiliation(s)
- Lars Jørn Jensen
- a Departments of Veterinary Clinical and Animal Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Morten Schak Nielsen
- b Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Max Salomonsson
- b Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Charlotte Mehlin Sørensen
- b Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
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7
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Ardanaz N, Pagano PJ. Hydrogen Peroxide as a Paracrine Vascular Mediator: Regulation and Signaling Leading to Dysfunction. Exp Biol Med (Maywood) 2016; 231:237-51. [PMID: 16514169 DOI: 10.1177/153537020623100302] [Citation(s) in RCA: 166] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Numerous studies have demonstrated the ability of a variety of vascular cells, including endothelial cells, smooth muscle cells, and fibroblasts, to produce reactive oxygen species (ROS). Until recently, major emphasis was placed on the production of superoxide anion (O2–) in the vasculature as a result of its ability to directly attenuate the biological activity of endothelium-derived nitric oxide (NO). The short half-life and radius of diffusion of O2– drastically limit the role of this ROS as an important paracrine hormone in vascular biology. On the contrary, in recent years, the O2– metabolite hydrogen peroxide (H2O2) has increasingly been viewed as an important cellular signaling agent in its own right, capable of modulating both contractile and growth-promoting pathways with more far-reaching effects. In this review, we will assess the vascular production of H2O2, its regulation by endogenous scavenger systems, and its ability to activate a variety of vascular signaling pathways, thereby leading to vascular contraction and growth. This discussion will include the ability of H2O2 to (i) Initiate calcium flux as well as (ii) stimulate pathways leading to sensitization of contractile elements to calcium. The latter involves a variety of protein kinases that have also been strongly implicated in vascular hypertrophy. Previous Intensive study has emphasized the ability of NADPH oxidase-derived O2– and H2O2 to activate these pathways in cultured smooth muscle cells. However, growing evidence indicates a considerably more complex array of unique oxidase systems in the endothelium, media, and adventitia that appear to participate in these deleterious effects in a sequential and temporal manner. Taken together, these findings seem consistent with a paracrine effect of H2O2 across the vascular wall.
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Affiliation(s)
- Noelia Ardanaz
- Hypertension and Vascular Research Division, RM 7044, E&R Building, Henry Ford Hospital, 2799 West Grand Boulevard, Detroit, MI 48202-2689, USA
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Fransen P, Van Hove CE, Leloup AJA, Schrijvers DM, De Meyer GRY, De Keulenaer GW. Effect of angiotensin II-induced arterial hypertension on the voltage-dependent contractions of mouse arteries. Pflugers Arch 2015; 468:257-67. [PMID: 26432297 DOI: 10.1007/s00424-015-1737-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 09/22/2015] [Indexed: 11/28/2022]
Abstract
Arterial hypertension (AHT) affects the voltage dependency of L-type Ca(2+) channels in cardiomyocytes. We analyzed the effect of angiotensin II (AngII)-induced AHT on L-type Ca(2+) channel-mediated isometric contractions in conduit arteries. AHT was induced in C57Bl6 mice with AngII-filled osmotic mini-pumps (4 weeks). Normotensive mice treated with saline-filled osmotic mini-pumps were used for comparison. Voltage-dependent contractions mediated by L-type Ca(2+) channels were studied in vaso-reactive studies in vitro in isolated aortic and femoral arteries by using extracellular K(+) concentration-response (KDR) experiments. In aortic segments, AngII-induced AHT significantly sensitized isometric contractions induced by elevated extracellular K(+) and depolarization. This sensitization was partly prevented by normalizing blood pressure with hydralazine, suggesting that it was caused by AHT rather than by direct AngII effects on aortic smooth muscle cells. The EC50 for extracellular K(+) obtained in vitro correlated significantly with the rise in arterial blood pressure induced by AngII in vivo. The AHT-induced sensitization persisted when aortic segments were exposed to levcromakalim or to inhibitors of basal nitric oxide release. Consistent with these observations, AngII-treatment also sensitized the vaso-relaxing effects of the L-type Ca(2+) channel blocker diltiazem during K(+)-induced contractions. Unlike aorta, AngII-treatment desensitized the isometric contractions to depolarization in femoral arteries pointing to vascular bed specific responses of arteries to hypertension. AHT affects the voltage-dependent L-type Ca(2+) channel-mediated contraction of conduit arteries. This effect may contribute to the decreased vascular compliance in AHT and explain the efficacy of Ca(2+) channel blockers to reduce vascular stiffness and central blood pressure in AHT.
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Affiliation(s)
- Paul Fransen
- Department of Pharmaceutical Sciences, Physiopharmacology, Campus Drie Eiken, University of Antwerp, T2, Universiteitsplein 1, 2610, Antwerp, Belgium.
| | - Cor E Van Hove
- Faculty of Medicine & Health Sciences, Pharmacology, Campus Drie Eiken, University of Antwerp, T2, Universiteitsplein 1, 2610, Antwerp, Belgium
| | - Arthur J A Leloup
- Department of Pharmaceutical Sciences, Physiopharmacology, Campus Drie Eiken, University of Antwerp, T2, Universiteitsplein 1, 2610, Antwerp, Belgium
| | - Dorien M Schrijvers
- Department of Pharmaceutical Sciences, Physiopharmacology, Campus Drie Eiken, University of Antwerp, T2, Universiteitsplein 1, 2610, Antwerp, Belgium
| | - Guido R Y De Meyer
- Department of Pharmaceutical Sciences, Physiopharmacology, Campus Drie Eiken, University of Antwerp, T2, Universiteitsplein 1, 2610, Antwerp, Belgium
| | - Gilles W De Keulenaer
- Department of Pharmaceutical Sciences, Physiopharmacology, Campus Drie Eiken, University of Antwerp, T2, Universiteitsplein 1, 2610, Antwerp, Belgium
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9
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Fransen P, Van Hove CE, Leloup AJA, Martinet W, De Meyer GRY, Lemmens K, Bult H, Schrijvers DM. Dissecting out the complex Ca2+-mediated phenylephrine-induced contractions of mouse aortic segments. PLoS One 2015; 10:e0121634. [PMID: 25803863 PMCID: PMC4372603 DOI: 10.1371/journal.pone.0121634] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 02/12/2015] [Indexed: 01/04/2023] Open
Abstract
L-type Ca2+ channel (VGCC) mediated Ca2+ influx in vascular smooth muscle cells (VSMC) contributes to the functional properties of large arteries in arterial stiffening and central blood pressure regulation. How this influx relates to steady-state contractions elicited by α1-adrenoreceptor stimulation and how it is modulated by small variations in resting membrane potential (Vm) of VSMC is not clear yet. Here, we show that α1-adrenoreceptor stimulation of aortic segments of C57Bl6 mice with phenylephrine (PE) causes phasic and tonic contractions. By studying the relationship between Ca2+ mobilisation and isometric tension, it was found that the phasic contraction was due to intracellular Ca2+ release and the tonic contraction determined by Ca2+ influx. The latter component involves both Ca2+ influx via VGCC and via non-selective cation channels (NSCC). Influx via VGCC occurs only within the window voltage range of the channel. Modulation of this window Ca2+ influx by small variations of the VSMC Vm causes substantial effects on the contractile performance of aortic segments. The relative contribution of VGCC and NSCC to the contraction by α1-adrenoceptor stimulation could be manipulated by increasing intracellular Ca2+ release from non-contractile sarcoplasmic reticulum Ca2+ stores. Results of this study point to a complex interactions between α1-adrenoceptor-mediated VSMC contractile performance and Ca2+ release form contractile or non-contractile Ca2+ stores with concomitant Ca2+ influx. Given the importance of VGCC and their blockers in arterial stiffening and hypertension, they further point toward an additional role of NSCC (and NSCC blockers) herein.
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Affiliation(s)
- Paul Fransen
- Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
- * E-mail:
| | - Cor E. Van Hove
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Arthur J. A. Leloup
- Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
| | - Wim Martinet
- Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
| | | | - Katrien Lemmens
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Hidde Bult
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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Kapela A, Bezerianos A, Tsoukias NM. A mathematical model of vasoreactivity in rat mesenteric arterioles: I. Myoendothelial communication. Microcirculation 2010; 16:694-713. [PMID: 19905969 DOI: 10.3109/10739680903177539] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
To study the effect of myoendothelial communication on vascular reactivity, we integrated detailed mathematical models of Ca(2+) dynamics and membrane electrophysiology in arteriolar smooth muscle (SMC) and endothelial (EC) cells. Cells are coupled through the exchange of Ca(2+), Cl(-), K(+), and Na(+) ions, inositol 1,4,5-triphosphate (IP(3)), and the paracrine diffusion of nitric oxide (NO). EC stimulation reduces intracellular Ca(2+) ([Ca(2+)](i)) in the SMC by transmitting a hyperpolarizing current carried primarily by K(+). The NO-independent endothelium-derived hyperpolarization was abolished in a synergistic-like manner by inhibition of EC SK(Ca) and IK(Ca) channels. During NE stimulation, IP(3) diffusing from the SMC induces EC Ca(2+) release, which, in turn, moderates SMC depolarization and [Ca(2+)](i) elevation. On the contrary, SMC [Ca(2+)](i) was not affected by EC-derived IP(3). Myoendothelial Ca(2+) fluxes had no effect in either cell. The EC exerts a stabilizing effect on calcium-induced calcium release-dependent SMC Ca(2+) oscillations by increasing the norepinephrine concentration window for oscillations. We conclude that a model based on independent data for subcellular components can capture major features of the integrated vessel behavior. This study provides a tissue-specific approach for analyzing complex signaling mechanisms in the vasculature.
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Affiliation(s)
- Adam Kapela
- Department of Biomedical Engineering, Florida International University, Miami, Florida, USA
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Abstract
Hypertension affects approximately 25% of adults and is a major risk factor for cardiovascular disease. Although there are currently adequate therapeutic options for humans with hypertension, the molecular mechanisms underlying hypertension are still relatively unknown. The generation of hypertensive animal models provides an excellent modality to not only study the pathophysiology but also test innovative therapeutics. This chapter describes the detailed methods that utilize the drinking water of rats to develop models of nitric oxide synthase (NOS) inhibition-induced, guanosine triphosphate cyclohydrolase (GTPCH) inhibition-induced, and glucocorticoid-induced hypertension.
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12
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Abstract
Accumulating evidence supports the importance of redox signaling in the pathogenesis and progression of hypertension. Redox signaling is implicated in many different physiological and pathological processes in the vasculature. High blood pressure is in part determined by elevated total peripheral vascular resistance, which is ascribed to dysregulation of vasomotor function and structural remodeling of blood vessels. Aberrant redox signaling, usually induced by excessive production of reactive oxygen species (ROS) and/or by decreases in antioxidant activity, can induce alteration of vascular function. ROS increase vascular tone by influencing the regulatory role of endothelium and by direct effects on the contractility of vascular smooth muscle. ROS contribute to vascular remodeling by influencing phenotype modulation of vascular smooth muscle cells, aberrant growth and death of vascular cells, cell migration, and extracellular matrix (ECM) reorganization. Thus, there are diverse roles of the vascular redox system in hypertension, suggesting that the complexity of redox signaling in distinct spatial spectrums should be considered for a better understanding of hypertension.
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Affiliation(s)
- Moo Yeol Lee
- Department of Medicine, Division of Cardiology, Emory University, Atlanta, Georgia 30322, USA
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Voltage-gated K+ channel dysfunction in myocytes from a dog model of subarachnoid hemorrhage. J Cereb Blood Flow Metab 2008; 28:797-811. [PMID: 17987046 DOI: 10.1038/sj.jcbfm.9600577] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Delayed cerebral vasospasm after subarachnoid hemorrhage is primarily due to sustained contraction of arterial smooth muscle cells. Its pathogenesis remains unclear. The degree of arterial constriction is regulated by membrane potential that in turn is determined predominately by K+ conductance (GK). Here, we identified the main voltage-gated K+ (Kv) channels contributing to outward delayed rectifier currents in dog basilar artery smooth muscle as Kv2 class through a combination of electrophysiological and pharmacological methods. Kv2 current density was nearly halved in vasospastic myocytes after subarachnoid hemorrhage (SAH) in dogs, and Kv2.1 and Kv2.2 were downregulated in vasospastic myocytes when examined by quantitative mRNA, Western blotting, and immunohistochemistry. Vasospastic myocytes were depolarized and had a smaller contribution of GK toward maintenance of their membrane potential. Pharmacological block of Kv current in control myocytes mimicked the depolarization observed in vasospastic arteries. The degree of membrane depolarization was found to be compatible with the amount of vasoconstriction observed after SAH. We conclude that Kv2 dysfunction after SAH contributes to the pathogenesis of delayed cerebral vasospasm. This may confer a novel target for treatment of delayed cerebral vasospasm.
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Northcott CA, Hayflick J, Watts SW. Upregulated function of phosphatidylinositol-3-kinase in genetically hypertensive rats: a moderator of arterial hypercontractility. Clin Exp Pharmacol Physiol 2005; 32:851-8. [PMID: 16173947 DOI: 10.1111/j.1440-1681.2010.04276.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. The growth enzyme phosphatidylinositol 3-kinase (PI3K) was recently implicated in the mediation of arterial spontaneous tone, an event observed in arteries from hypertensive, but not normotensive, subjects that contributes to changes in total peripheral resistance in the hypertensive state. We have shown this occurrence in experimentally induced models of hypertension. However, because the majority of hypertension is genetically based, it is important to demonstrate a similar change in genetically hypertensive animals. 2. Aorta from spontaneously hypertensive rats (SHR; systolic blood pressure = 183 +/- 4 mmHg) and Wistar Kyoto (WKY) rats (115 +/- 2 mmHg) were isolated for the measurement of isometric contractile force. Aorta from SHR displayed small increases (approximately 5% maximum phenylephrine (PE)-induced contraction) in spontaneous tone, whereas aorta from WKY rats displayed none. The non-selective PI3K inhibitor LY294002 (20 micromol/L) and the selective inhibitor of the p110delta catalytic subunit of PI3K IC87114 (20 micromol/L) caused a fall of basal tone in SHR aorta (20 +/- 7 and 24 +/- 6% of the initial PE contraction, respectively), but did not alter tone in arteries from WKY rats. LY294002, but not IC87114, normalized the increased potency of noradrenaline (NA) observed in aorta from SHR (-log EC50 values for NA in the presence of vehicle in WKY rats and SHR 7.5 +/- 0.1 and 7.8 +/- 0.1, respectively (P < 0.05); -log EC(50) values for NA in the presence of LY294002 in WKY rats and SHR 7.0 +/- 0.1 and 7.0 +/- 0.1, respectively). 3. Biochemical expression of the p110 catalytic and p85 regulator subunits of PI3K in western analyses revealed no difference in expression of the regulatory p85alpha or p110alpha protein subunits between WKY rats and SHR; p110gamma was not detected. In contrast, p110delta expression was increased greater than 30% in aorta from SHR compared with WKY rats (827.6 +/- 88.5 vs 576.8 +/- 53.4 arbitrary densitometry units, respectively). Immunohistochemical analyses revealed expression of the p110delta isoform in the smooth muscle of arteries. 4. These data underscore the relevance of an enzyme historically classified as one committed to growth/anti-apoptosis in modifying contractility and supports involvement of PI3K in genetically based hypertension.
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Affiliation(s)
- Carrie A Northcott
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824-1317, USA
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Zhang J, Lee MY, Cavalli M, Chen L, Berra-Romani R, Balke CW, Bianchi G, Ferrari P, Hamlyn JM, Iwamoto T, Lingrel JB, Matteson DR, Wier WG, Blaustein MP. Sodium pump alpha2 subunits control myogenic tone and blood pressure in mice. J Physiol 2005; 569:243-56. [PMID: 16166162 PMCID: PMC1464198 DOI: 10.1113/jphysiol.2005.091801] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A key question in hypertension is: How is long-term blood pressure controlled? A clue is that chronic salt retention elevates an endogenous ouabain-like compound (EOLC) and induces salt-dependent hypertension mediated by Na(+)/Ca(2)(+) exchange (NCX). The precise mechanism, however, is unresolved. Here we study blood pressure and isolated small arteries of mice with reduced expression of Na(+) pump alpha1 (alpha1(+/-)) or alpha2 (alpha2(+/-)) catalytic subunits. Both low-dose ouabain (1-100 nm; inhibits only alpha2) and high-dose ouabain (> or =1 microm; inhibits alpha1) elevate myocyte Ca(2)(+) and constrict arteries from alpha1(+/-), as well as alpha2(+/-) and wild-type mice. Nevertheless, only mice with reduced alpha2 Na(+) pump activity (alpha2(+/-)), and not alpha1 (alpha1(+/-)), have elevated blood pressure. Also, isolated, pressurized arteries from alpha2(+/-), but not alpha1(+/-), have increased myogenic tone. Ouabain antagonists (PST 2238 and canrenone) and NCX blockers (SEA0400 and KB-R7943) normalize myogenic tone in ouabain-treated arteries. Only the NCX blockers normalize the elevated myogenic tone in alpha2(+/-) arteries because this tone is ouabain independent. All four agents are known to lower blood pressure in salt-dependent and ouabain-induced hypertension. Thus, chronically reduced alpha2 activity (alpha2(+/-) or chronic ouabain) apparently regulates myogenic tone and long-term blood pressure whereas reduced alpha1 activity (alpha1(+/-)) plays no persistent role: the in vivo changes in blood pressure reflect the in vitro changes in myogenic tone. Accordingly, in salt-dependent hypertension, EOLC probably increases vascular resistance and blood pressure by reducing alpha2 Na(+) pump activity and promoting Ca(2)(+) entry via NCX in myocytes.
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Affiliation(s)
- Jin Zhang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Bratz IN, Swafford AN, Kanagy NL, Dick GM. Reduced functional expression of K+channels in vascular smooth muscle cells from rats made hypertensive withNω-nitro-l-arginine. Am J Physiol Heart Circ Physiol 2005; 289:H1284-90. [PMID: 15879481 DOI: 10.1152/ajpheart.01053.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Smooth muscle membrane potential is determined, in part, by K+channels. In the companion paper to this article (Bratz IN, Dick GM, Partridge LD, and Kanagy NL. Am J Physiol Heart Circ Physiol 289: H1277–H1283, 2005), we demonstrated that superior mesenteric arteries from rats made hypertensive with Nω-nitro-l-arginine (l-NNA) are depolarized and express less K+channel protein compared with those from normotensive rats. In the present study, we used patch-clamp techniques to test the hypothesis that l-NNA-induced hypertension reduces the functional expression of K+channels in smooth muscle. In whole cell experiments using a Ca2+-free pipette solution, current at 0 mV, largely due to voltage-dependent K+(KV) channels, was reduced ∼60% by hypertension (2.7 ± 0.4 vs. 1.1 ± 0.2 pA/pF). Current at +100 mV with 300 nM free Ca2+, largely due to large-conductance Ca2+-activated K+(BKCa) channels, was reduced ∼40% by hypertension (181 ± 24 vs. 101 ± 28 pA/pF). Current blocked by 3 mM 4-aminopyridine, an inhibitor of many KVchannel types, was reduced ∼50% by hypertension (1.0 ± 0.4 vs. 0.5 ± 0.2 pA/pF). Current blocked by 1 mM tetraethylammonium, an inhibitor of BKCachannels, was reduced ∼40% by hypertension (86 ± 14 vs. 53 ± 19 pA/pF). Differences in BKCacurrent magnitude are not attributable to changes in single-channel conductance or Ca2+/voltage sensitivity. The data support the hypothesis that l-NNA-induced hypertension reduces K+current in vascular smooth muscle. Reduced molecular and functional expression of K+channels may partly explain the depolarization and augmented contractile sensitivity of smooth muscle from l-NNA-treated rats.
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Affiliation(s)
- Ian N Bratz
- Department of Physiology, LSU Health Sciences Center, 1901 Perdido St., New Orleans, LA 70112, USA
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Yang J, Clark JW, Bryan RM, Robertson CS. Mathematical modeling of the nitric oxide/cGMP pathway in the vascular smooth muscle cell. Am J Physiol Heart Circ Physiol 2005; 289:H886-97. [PMID: 15833804 DOI: 10.1152/ajpheart.00216.2004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nitric oxide (NO)/cGMP pathway in the vascular smooth muscle cell (VSMC) is an important cellular signaling system for the regulation of VSMC relaxation. We present a mathematical model to investigate the underlying mechanisms of this pathway. The model describes the flow of NO-driven signal transduction: NO activation of soluble guanylate cyclase (sGC), sGC- and phosphodiesterase-catalyzed cGMP production and degradation, cGMP-mediated regulation of protein targets including the Ca2+-activated K+ (KCa) channel, and the myosin contractile system. Model simulations reproduce major NO/cGMP-induced VSMC relaxation effects, including intracellular Ca2+ concentration reduction and Ca2+ desensitization of myosin phosphorylation and force generation. Using the model, we examine several testable principles. 1) Rapid sGC desensitization is caused by end-product cGMP feedback inhibition; a large fraction of the steady-state sGC population is in an inactivated intermediate state, and cGMP production is limited well below maximum. 2) NO activates the K(Ca) channel with both cGMP-dependent and -independent mechanisms; moderate NO concentration affects the K(Ca) via the cGMP-dependent pathway, whereas higher NO concentration is accommodated by a cGMP-independent mechanism. 3) Chronic NO synthase inhibition may cause underexpressions of K+ channels including inward rectifier and K(Ca) channels. 4) Ca2+ desensitization of the contractile system is distinguished from Ca2+ sensitivity of myosin phosphorylation. The model integrates these interactions among the heterogeneous components of the NO signaling system and can serve as a general modeling framework for studying NO-mediated VSMC relaxation under various physiological and pathological conditions. New data can be readily incorporated into this framework for interpretation and possible modification and improvement of the model.
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Affiliation(s)
- Jin Yang
- Department of Bioengineering, MS-366, Rice Univ., Houston, TX 77005, USA
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Bratz IN, Dick GM, Partridge LD, Kanagy NL. Reduced molecular expression of K(+) channel proteins in vascular smooth muscle from rats made hypertensive with N{omega}-nitro-L-arginine. Am J Physiol Heart Circ Physiol 2005; 289:H1277-83. [PMID: 15792990 DOI: 10.1152/ajpheart.01052.2004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Smooth muscle membrane potential (E(m)) depends on K(+) channels, and arteries from rats made hypertensive with N(omega)-nitro-l-arginine (LHR) are depolarized compared with control. We hypothesized that decreased K(+) channel function, due to decreased K(+) channel protein expression, underlies E(m) depolarization. Furthermore, K(+) channel blockers should move control E(m) (-46 +/- 1 mV) toward that in LHR (-37 +/- 2 mV) and normalize contraction. The E(m) vs. K(+) relationship was less steep in LHR (23 +/- 2 vs. 28 +/- 1 mV/log K(+) concentration), and contractile sensitivity to K(+) was increased (EC(50) = 37 +/- 1 vs. 23 +/- 1 mM). Iberiotoxin (10 nM), an inhibitor of large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels, depolarized control and LHR E(m) to -35 +/- 1 and -30 +/- 2 mV, respectively; however, effects on K(+) sensitivity were more profound in LHR (EC(50) = 25 +/- 2 vs. 15 +/- 3 mM). The voltage-dependent K(+) (K(V)) channel blocker 4-aminopyridine (3 mM) depolarized control E(m) to the level of LHR (-28 +/- 1 vs. -28 +/- 1 mV); however, effects on K(+) sensitivity were greater in LHR (EC(50) = 17 +/- 4 vs. 4 +/- 4 mM). Western blots revealed reduced BK(Ca) and K(V)1.5 channel expression in LHR arteries. The findings suggest that diminished expression of K(+) channels contributes to depolarization and enhanced contractile sensitivity. These conclusions are supported by direct electrophysiological assessment of BK(Ca) and K(V) channel function in control and LHR smooth muscle cells.
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Affiliation(s)
- Ian N Bratz
- Department of Physiology, LSU Health Sciences Center, 1901 Perdido St., New Orleans, LA 70112, USA
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Bratz IN, Kanagy NL. Nitric oxide synthase-inhibition hypertension is associated with altered endothelial cyclooxygenase function. Am J Physiol Heart Circ Physiol 2004; 287:H2394-401. [PMID: 15319202 DOI: 10.1152/ajpheart.00628.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We reported previously that endothelium-intact superior mesenteric arteries (SMA) from Nω-nitro-l-arginine (l-NNA)-treated hypertensive rats (LHR) contract more to norepinephrine (NE) than SMA from control rats. Others have shown that nitric oxide (NO) synthase (NOS) inhibition increases cyclooxygenase (COX) function and expression. We hypothesized that augmented vascular sensitivity to NE in LHR arteries is caused by decreased NOS-induced dilation and increased COX product-induced constriction. We observed that the EC50 for NE is lower in LHR SMA compared with control SMA (control −6.37 ± 0.04, LHR −7.89 ± 0.09 log mol/l; P < 0.05). Endothelium removal lowered the EC50 (control −7.95 ± 0.11, LHR −8.44 ± 0.13 log mol/l; P < 0.05) and increased maximum tension in control (control 1,036 ± 38 vs. 893 ± 21 mg; P < 0.05) but not LHR (928 ± 30 vs. 1,066 ± 31 mg) SMA. Thus augmented NE sensitivity in LHR SMA depends largely on decreased endothelial dilation. NOS inhibition (l-NNA, 10−4 mol/l) increased maximum tension and EC50 in control arteries but not in LHR arteries. In contrast, COX inhibition decreased maximum tension in control arteries, suggesting that COX products augment contraction. Indomethacin did not affect NE-induced contraction in l-NNA-treated or denuded arteries. In control SMA loaded with the fluorescent NO indicator 4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate, indomethacin increased and l-NNA decreased NO release. Therefore, COX products appear to inhibit NO production to augment NE-induced contraction. With chronic NOS inhibition, this modulating influence is greatly diminished. Thus, in NOS-inhibition hypertension, decreased activity of both COX and NOS pathways profoundly disrupts endothelial modulation of contraction.
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Affiliation(s)
- Ian N Bratz
- Vascular Physiology Research Group, MSC 08-4750, Dept. of Cell Biology and Physiology, 1 Univ. of New Mexico Health Sciences Center, Albuquerque, NM 87131-0218, USA
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