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Spatial and temporal characteristics of Ca2+ signaling in endothelial cells of intact rat tail artery. Artery Res 2013. [DOI: 10.1016/j.artres.2013.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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2
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Moccia F, Berra-Romani R, Tanzi F. Update on vascular endothelial Ca 2+ signalling: A tale of ion channels, pumps and transporters. World J Biol Chem 2012; 3:127-58. [PMID: 22905291 PMCID: PMC3421132 DOI: 10.4331/wjbc.v3.i7.127] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/04/2012] [Accepted: 07/11/2012] [Indexed: 02/05/2023] Open
Abstract
A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which are located both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions.
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Affiliation(s)
- Francesco Moccia
- Francesco Moccia, Franco Tanzi, Department of Biology and Biotechnologies "Lazzaro Spallanzani", Laboratory of Physiology, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
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3
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Mumtaz S, Burdyga G, Borisova L, Wray S, Burdyga T. The mechanism of agonist induced Ca2+ signalling in intact endothelial cells studied confocally in in situ arteries. Cell Calcium 2010; 49:66-77. [PMID: 21176847 PMCID: PMC3098389 DOI: 10.1016/j.ceca.2010.11.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 11/24/2010] [Accepted: 11/25/2010] [Indexed: 11/25/2022]
Abstract
In endothelial cells there remain uncertainties in the details of how Ca2+ signals are generated and maintained, especially in intact preparations. In particular the role of the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA), in contributing to the components of agonist-induced signals is unclear. The aim of this work was to increase understanding of the detailed mechanism of Ca2+ signalling in endothelial cells using real time confocal imaging of Fluo-4 loaded intact rat tail arteries in response to muscarinic stimulation. In particular we have focused on the role of SERCA, and its interplay with capacitative Ca2+ entry (CCE) and ER Ca2+ release and uptake. We have determined its contribution to the Ca2+ signal and how it varies with different physiological stimuli, including single and repeated carbachol applications and brief and prolonged exposures. In agreement with previous work, carbachol stimulated a rise in intracellular Ca2+ in the endothelial cells, consisting of a rapid initial phase, then a plateau upon which oscillations of Ca2+ were superimposed, followed by a decline to basal Ca2+ levels upon carbachol removal. Our data support the following conclusions: (i) the size (amplitude and duration) of the Ca2+ spike and early oscillations are limited by SERCA activity, thus both are increased if SERCA is inhibited. (ii) SERCA activity is such that brief applications of carbachol do not trigger CCE, presumably because the fall in luminal Ca2+ is not sufficient to trigger it. However, longer applications sufficient to deplete the ER or even partial SERCA inhibition stimulate CCE. (iii) Ca2+ entry occurs via STIM-mediated CCE and SERCA contributes to the cessation of CCE. In conclusion our data show how SERCA function is crucial to shaping endothelial cell Ca signals and its dynamic interplay with both CCE and ER Ca releases.
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Affiliation(s)
- S Mumtaz
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, UK
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4
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Rehn M, Diener M. Effect of the stable thromboxane derivative, carbocyclic thromboxane A2, on membrane potential of rat myenteric neurones in culture. Neurogastroenterol Motil 2006; 18:1084-92. [PMID: 17109692 DOI: 10.1111/j.1365-2982.2006.00840.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The effects of carbocyclic thromboxane A(2) (cTXA(2); 10(-6) mol L(-1)) on membrane potential and cytosolic Ca(2+) concentration were measured with the whole-cell patch-clamp or the fura-2 method, respectively, at rat myenteric ganglia. cTXA(2) caused a hyperpolarization of myenteric neurones from -19.3 +/- 2.5 to -29.3 +/- 2.3 mV. In addition, the eicosanoid potentiated the carbachol-induced depolarization from 4.2 +/- 1.0 mV under control conditions to 11.1 +/- 1.1 mV in the presence of the cTXA(2) (n = 9). The hyperpolarization was abolished by internal application of CsCl (140 mmol L(-1)), a non-selective blocker of K(+) channels, or EGTA (11 mmol L(-1)in the pipette solution), a chelator of intracellular Ca(2+). A similar inhibition was observed in the presence of charybdotoxin (10(-7) mol L(-1)). Fura-2 imaging experiments revealed a cTXA(2)-evoked increase in the intracellular Ca(2+) concentration as indicated by a rise in the fura-2 ratio signal. This response was mediated by a release of Ca(2+) from intracellular stores as sarcoplasmic-endoplasmic reticulum Ca(2+)-ATPase blockade with cyclopiazonic acid (5 x 10(-5) mol L(-1)) completely abolished the response to cTXA(2). A similar inhibition was observed after blockade of phospholipase C with U-73122 (10(-5) mol L(-1)). These results suggest an activation of Ca(2+)-activated K(+) channels by cTXA(2) after stimulation of phospholipase C.
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Affiliation(s)
- M Rehn
- Institute for Veterinary Physiology, University of Giessen, Germany
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5
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Sweeney M, Jones CJP, Greenwood SL, Baker PN, Taggart MJ. Ultrastructural features of smooth muscle and endothelial cells of isolated isobaric human placental and maternal arteries. Placenta 2005; 27:635-47. [PMID: 16029888 DOI: 10.1016/j.placenta.2005.05.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Revised: 05/13/2005] [Accepted: 05/14/2005] [Indexed: 11/18/2022]
Abstract
The ability of a blood vessel to develop tone is dependent upon morphological parameters of the smooth muscle cells (SMC), including density, relationship with the endothelium and subcellular distribution of myofilaments and intracellular organelles. Consequently, wall ultrastructure of isolated human placental chorionic plate arteries (n=12), fixed when pressurised to mimic their in vivo geometry, was examined qualitatively using electron microscopy, and compared with maternal arteries (omental, n=10, myometrial, n=6). Arteries from women with uncomplicated pregnancy were tested for contractile viability before fixing, with some vessels post-fixed in osmium-ferricyanide for sarcoplasmic reticulum (SR) identification. In contrast to maternal arteries, placental arteries had no internal elastic lamina but exhibited considerable extracellular matrix separating circularly orientated SMC. Human SMC contained tightly packed arrays of myofilaments running parallel to the plasma membrane, enveloping cellular organelles. Synthetic SMC, with few myofilaments and much rough SR, were observed in placental arteries only. SR in SMC from maternal arteries was located centrally, often encircling mitochondria, and also near the plasma membrane associated with caveolae. Positive SR staining was rarely observed in SMC of placental arteries. This study highlights ultrastructural differences between placental and maternal arteries that may underlie specialised mechanisms of regulating vascular tone in the placenta.
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MESH Headings
- Adult
- Chorion/blood supply
- Chorion/physiology
- Electromyography/methods
- Endothelium, Vascular/physiology
- Endothelium, Vascular/ultrastructure
- Female
- Humans
- Microscopy, Electron, Transmission
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Muscle, Smooth, Vascular/ultrastructure
- Myometrium/blood supply
- Myometrium/physiology
- Omentum/blood supply
- Omentum/physiology
- Placental Circulation/drug effects
- Placental Circulation/physiology
- Pregnancy
- Pressure
- Sarcoplasmic Reticulum/ultrastructure
- Umbilical Arteries/physiology
- Umbilical Arteries/ultrastructure
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Affiliation(s)
- M Sweeney
- Maternal and Fetal Health Research Centre, Division of Human Development, University of Manchester, 1st Floor St. Mary's Hospital, Whitworth Park, Manchester M13 0JH, UK.
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6
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Burdyga T, Shmygol A, Eisner DA, Wray S. A new technique for simultaneous and in situ measurements of Ca2+ signals in arteriolar smooth muscle and endothelial cells. Cell Calcium 2003; 34:27-33. [PMID: 12767890 DOI: 10.1016/s0143-4160(03)00019-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We report here the first local and global Ca(2+) measurements made from in situ terminal arterioles. The advantages of the method are that there is minimal disturbance to the vessels, which retain their relationship to the tissue they are supplying (rat ureter) and the small size of vessel that can be studied. Good loading with the Ca(2+) indicator, Fluo-4 was obtained, and confocal sectioning through the tissue enabled vascular smooth muscle and endothelial cells to be clearly seen, along with red blood cells, nerve endings and the ureteric smooth muscle cells. We find the terminal arterioles to be extremely active, both spontaneously and in response to nor-adrenaline stimulation, with Ca(2+) sparks occurring in the vascular myocytes and Ca(2+) puffs in the endothelial cells. Even under resting conditions, endothelial cells produced oscillations and waves, which could pass from cell to cell, whereas the vascular myocytes only produced waves in response to agonist stimulation, and with no increase in the frequency of Ca(2+) sparks, and no spread from cell to cell. We compare our data to those obtained in dissected intact vessels and single cells. We conclude that this approach is a convenient and useful method for studying inter- and intracellular Ca(2+) signalling events and communication between cell types, particularly in very small vessels.
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MESH Headings
- Action Potentials/drug effects
- Action Potentials/physiology
- Aniline Compounds
- Animals
- Arterioles/cytology
- Arterioles/metabolism
- Calcium/analysis
- Calcium/metabolism
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Histocytochemistry/instrumentation
- Histocytochemistry/methods
- Microscopy, Confocal/instrumentation
- Microscopy, Confocal/methods
- Muscle Contraction/drug effects
- Muscle Contraction/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Norepinephrine/pharmacology
- Rats
- Ureter/blood supply
- Ureter/cytology
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
- Xanthenes
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Affiliation(s)
- T Burdyga
- The Physiological Laboratory, Department of Physiology, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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7
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Abstract
Endothelial cells (EC) form a unique signal-transducing surface in the vascular system. The abundance of ion channels in the plasma membrane of these nonexcitable cells has raised questions about their functional role. This review presents evidence for the involvement of ion channels in endothelial cell functions controlled by intracellular Ca(2+) signals, such as the production and release of many vasoactive factors, e.g., nitric oxide and PGI(2). In addition, ion channels may be involved in the regulation of the traffic of macromolecules by endocytosis, transcytosis, the biosynthetic-secretory pathway, and exocytosis, e.g., tissue factor pathway inhibitor, von Willebrand factor, and tissue plasminogen activator. Ion channels are also involved in controlling intercellular permeability, EC proliferation, and angiogenesis. These functions are supported or triggered via ion channels, which either provide Ca(2+)-entry pathways or stabilize the driving force for Ca(2+) influx through these pathways. These Ca(2+)-entry pathways comprise agonist-activated nonselective Ca(2+)-permeable cation channels, cyclic nucleotide-activated nonselective cation channels, and store-operated Ca(2+) channels or capacitative Ca(2+) entry. At least some of these channels appear to be expressed by genes of the trp family. The driving force for Ca(2+) entry is mainly controlled by large-conductance Ca(2+)-dependent BK(Ca) channels (slo), inwardly rectifying K(+) channels (Kir2.1), and at least two types of Cl( -) channels, i.e., the Ca(2+)-activated Cl(-) channel and the housekeeping, volume-regulated anion channel (VRAC). In addition to their essential function in Ca(2+) signaling, VRAC channels are multifunctional, operate as a transport pathway for amino acids and organic osmolytes, and are possibly involved in endothelial cell proliferation and angiogenesis. Finally, we have also highlighted the role of ion channels as mechanosensors in EC. Plasmalemmal ion channels may signal rapid changes in hemodynamic forces, such as shear stress and biaxial tensile stress, but also changes in cell shape and cell volume to the cytoskeleton and the intracellular machinery for metabolite traffic and gene expression.
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Affiliation(s)
- B Nilius
- Department of Physiology, KU Leuven, Campus Gasthuisberg, Leuven, Belgium.
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8
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Ito K, Miyashita Y, Kasai H. Kinetic control of multiple forms of Ca(2+) spikes by inositol trisphosphate in pancreatic acinar cells. J Cell Biol 1999; 146:405-13. [PMID: 10427093 PMCID: PMC2156179 DOI: 10.1083/jcb.146.2.405] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The mechanisms of agonist-induced Ca(2+) spikes have been investigated using a caged inositol 1,4,5-trisphosphate (IP(3)) and a low-affinity Ca(2+) indicator, BTC, in pancreatic acinar cells. Rapid photolysis of caged IP(3) was able to reproduce acetylcholine (ACh)-induced three forms of Ca(2+) spikes: local Ca(2+) spikes and submicromolar (<1 microM) and micromolar (1-15 microM) global Ca(2+) spikes (Ca(2+) waves). These observations indicate that subcellular gradients of IP(3) sensitivity underlie all forms of ACh-induced Ca(2+) spikes, and that the amplitude and extent of Ca(2+) spikes are determined by the concentration of IP(3). IP(3)-induced local Ca(2+) spikes exhibited similar time courses to those generated by ACh, supporting a role for Ca(2+)-induced Ca(2+) release in local Ca(2+) spikes. In contrast, IP(3)- induced global Ca(2+) spikes were consistently faster than those evoked with ACh at all concentrations of IP(3) and ACh, suggesting that production of IP(3) via phospholipase C was slow and limited the spread of the Ca(2+) spikes. Indeed, gradual photolysis of caged IP(3) reproduced ACh-induced slow Ca(2+) spikes. Thus, local and global Ca(2+) spikes involve distinct mechanisms, and the kinetics of global Ca(2+) spikes depends on that of IP(3) production particularly in those cells such as acinar cells where heterogeneity in IP(3) sensitivity plays critical role.
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Affiliation(s)
- Koichi Ito
- Department of Physiology, Faculty of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yasushi Miyashita
- Department of Physiology, Faculty of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Haruo Kasai
- Department of Physiology, Faculty of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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9
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Isshiki M, Ando J, Korenaga R, Kogo H, Fujimoto T, Fujita T, Kamiya A. Endothelial Ca2+ waves preferentially originate at specific loci in caveolin-rich cell edges. Proc Natl Acad Sci U S A 1998; 95:5009-14. [PMID: 9560219 PMCID: PMC20204 DOI: 10.1073/pnas.95.9.5009] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Stimulation of endothelial cells (ECs) with ATP evoked an increase in intracellular Ca2+ concentration ([Ca2+]i). In a single bovine aortic EC, the [Ca2+]i rise started at a specific peripheral locus and propagated throughout the entire cell as a Ca2+ wave. The initiation locus was constant upon repeated stimulation with ATP or other agonists (bradykinin and thrombin). The Ca2+ wave was unaffected by the removal of extracellular Ca2+, demonstrating its dependence on intracellular Ca2+ release. Microinjection of heparin into the cell inhibited the ATP-induced Ca2+ responses, indicating that the Ca2+ wave is at least partly mediated by the inositol 1,4, 5-trisphosphate receptor. Immunofluorescence staining revealed that caveolin, a marker protein for caveolae, is distributed heterogeneously in the cell and that Ca2+ waves preferentially originate at caveolin-rich cell edges. In contrast to caveolin, internalized transferrin and subunits of the clathrin-associated adaptor complexes such as adaptor protein-1 and -2 were diffusely distributed. Disruption of microtubules by Colcemid led to redistribution of caveolin away from the edges into the perinuclear center of the cell, and the ATP-induced [Ca2+]i increase was initiated on the rim of the centralized caveolin. Thus, caveolae may be involved in the initiation of ATP-induced Ca2+ waves in ECs.
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Affiliation(s)
- M Isshiki
- Department of Biomedical Engineering, Graduate School of Medicine, University of Tokyo 113-0033, Japan.
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10
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Unger GM, Bellrichard RL, Trinh BI, Sammak PJ. Quantitative assessment of leading edge adhesion: reattachment kinetics modulated by injury-derived intracellular calcium predict wound closure rates in endothelial monolayers. J Cell Physiol 1998; 174:217-31. [PMID: 9428808 DOI: 10.1002/(sici)1097-4652(199802)174:2<217::aid-jcp9>3.0.co;2-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Migrating cells continually develop new substrate attachments at the leading edge (LE) in order to maintain traction for movement. This study evaluates the relationship between LE adhesion and wound closure by modulating injury-derived intracellular free Ca2+ ([Ca2+]i) signaling in endothelial cell (EC) monolayers following scrape-wounding. These data show that brief treatment with increased extracellular Ca2+ ([Ca2+]e) during wounding accelerated wound area closure rates by 50-65%, while brief treatments with calcium influx inhibitors reduced rates by 30-50%. Fura-2 studies in wounded monolayers indicated supranormal [Ca2+]e during wounding increased (by 52%), while influx-inhibitors decreased (by 36%) the percentage of cells exhibiting elevated plateau [Ca2+]i levels. Quantitative time-lapse interference reflection microscopy (IRM) together with indirect alphavbeta3 integrin immunofluorescence was used to measure the effects of 100 microM Gd3+ and 5 mM [Ca2+]e treatment on fractional LE adhesion after wounding. Influx inhibition blocked development of increased injury-derived LE adhesion. Measurements indicated a linear relationship (r2 = 0.99, 0.98) between LE adhesion, development rates (quantified as an association rate constant) and steady state wound closure rates. Changes in filopodial activity, as indicated by phase contrast microscopy, did not correlate with changes in wound closure rates, but an association existed between the percentile peak [Ca2+]i response and the initiation of filopodial activity, suggesting a role for filopodia in mediating Ca2+-sensitive acceleration. Taken together, our data suggest that injury-derived [Ca2+]i signaling may regulate wound closure rates by an adhesion-mediated mechanism.
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Affiliation(s)
- G M Unger
- Department of Pharmacology, University of Minnesota, Minneapolis, USA
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Hüser J, Blatter LA. Elementary events of agonist-induced Ca2+ release in vascular endothelial cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:C1775-82. [PMID: 9374666 DOI: 10.1152/ajpcell.1997.273.5.c1775] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The subcellular spatial and temporal organization of agonist-induced Ca2+ signals was investigated in single cultured vascular endothelial cells. Extracellular application of ATP initiated a rapid increase of intracellular Ca2+ concentration ([Ca2+]i) in peripheral cytoplasmic processes from where activation propagated as a [Ca2+]i wave toward the central regions of the cell. The average propagation velocity of the [Ca2+]i wave in the peripheral processes was 20-60 microns/s, whereas in the central region the wave propagated at < 10 microns/s. The time course of the recovery of [Ca2+]i depended on the cell geometry. In the peripheral processes (i.e., regions with a high surface-to-volume ratio) [Ca2+]i declined monotonically, whereas in the central region [Ca2+]i decreased in an oscillatory fashion. Propagating [Ca2+]i waves were preceded by small, highly localized [Ca2+]i transients originating from 1- to 3-micron-wide regions. The average amplitude of these elementary events of Ca2+ release was 23 nM, and the underlying flux of Ca2+ amounted to approximately 1-2 x 10(-18) mol/s or approximately 0.3 pA, consistent with a Ca2+ flux through a single or small number of endoplasmic reticulum Ca(2+)-release channels.
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Affiliation(s)
- J Hüser
- Department of Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, USA
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12
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Kasai Y, Yamazawa T, Sakurai T, Taketani Y, Iino M. Endothelium-dependent frequency modulation of Ca2+ signalling in individual vascular smooth muscle cells of the rat. J Physiol 1997; 504 ( Pt 2):349-57. [PMID: 9365909 PMCID: PMC1159915 DOI: 10.1111/j.1469-7793.1997.349be.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. We visualized intracellular Ca2+ concentration ([Ca2+]i) changes, using fluo-3 as an indicator, of individual vascular smooth muscle cells and endothelial cells within intact rat tail arteries by confocal microscopy. 2. Using a piezo-driven objective, we focused on endothelial and smooth muscle cell layers alternately to obtain Ca2+ images of their cells. In the presence of 1 microM acetylcholine (ACh), individual endothelial cells responded with intermittent increases in the [Ca2+]i (Ca2+ oscillations). At the same time, the frequency of Ca2+ oscillations in smooth muscle cells induced by electrical stimulation of the perivascular sympathetic nerve was greatly decreased. 3. A [Ca2+]i rise during the oscillations in the endothelial cells propagated in the form of a wave along the long axis of the cells. 4. In the presence of a NO synthase inhibitor, no significant inhibitory effect of ACh on the Ca2+ signalling in the vascular smooth muscle cells was detected, although the Ca2+ oscillations in the endothelial cells persisted. 5. The inhibitory effect of ACh on the frequency of Ca2+ oscillations in the vascular smooth muscle cells was mimicked by 1 microM sodium nitroprusside, a NO donor. 6. These results indicate that Ca2+ waves and oscillations in vascular endothelial cells regulate NO production, which modulates vascular tone by decreasing the frequency of Ca2+ oscillations in smooth muscle cells activated by sympathetic agonists.
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Affiliation(s)
- Y Kasai
- Department of Pharmacology, Faculty of Medicine, University of Tokyo, Japan
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13
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Ohata H, Ujike Y, Momose K. Confocal imaging analysis of ATP-induced Ca2+ response in individual endothelial cells of the artery in situ. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 272:C1980-7. [PMID: 9227427 DOI: 10.1152/ajpcell.1997.272.6.c1980] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The mechanisms for mobilization of intracellular free Ca2+ have been studied in various types of isolated and cultured cells, but little is known about Ca2+ mobilization in individual cells in situ. We tried to establish imaging analysis of intracellular free Ca2+ concentration ([Ca2+]i) in individual cells loaded with the acetoxymethyl ester of fluo 3 in situ, using laser scanning confocal microscopy. The method permitted us to distinguish signals from endothelial and smooth muscle cells of guinea pig artery. Addition of ATP to the artery caused a transient increase in endothelial [Ca2+]i. It was concluded that the response was induced via P2Y purinoceptors, because adenosine 5'-O-(2-thiodiphosphate), but not UTP, caused a similar response independent of extracellular Ca2+. The percentage of cells that responded to ATP (1-10 microM) and the peak amplitude of the transient increase in [Ca2+]i were dose dependently increased. Using rapid xy-scanning and line-scanning modes, we confirmed that 10 microM ATP induced Ca2+ waves, at a rate of 10-30 microns/s, after a lag time of approximately 3 s. These results show that [Ca2+]i waves within endothelial cells are physiologically induced by ATP via P2Y purinoceptor, but not P2U purinoceptor, in aortic strips in situ. The method should be of use in the study of vascular physiology and pathophysiology.
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MESH Headings
- Adenosine Diphosphate/analogs & derivatives
- Adenosine Diphosphate/pharmacology
- Adenosine Triphosphate/pharmacology
- Aniline Compounds
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/physiology
- Calcium/metabolism
- Egtazic Acid/analogs & derivatives
- Egtazic Acid/pharmacology
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- Fluorescent Dyes
- Guinea Pigs
- In Vitro Techniques
- Kinetics
- Microscopy, Confocal/methods
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/physiology
- Receptors, Purinergic P2/drug effects
- Receptors, Purinergic P2/physiology
- Thionucleotides/pharmacology
- Uridine Triphosphate/pharmacology
- Xanthenes
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Affiliation(s)
- H Ohata
- Department of Pharmacology, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan
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14
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Hepworth TJ, Lawrie AM, Simpson AW. Okadaic acid induces the release of Ca2+ from intracellular stores in ECV304 endothelial cells. Cell Calcium 1997; 21:461-7. [PMID: 9223682 DOI: 10.1016/s0143-4160(97)90057-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effects of serine/threonine phosphatase inhibition on endothelial cell cytosolic free Ca2+ ([Ca2+]c) were investigated using okadaic acid and Fura-2-loaded ECV304 endothelial cells. When added to confluent adherent cells, 500 nM okadaic acid induced a transient and oscillatory elevation of [Ca2+]c both in the presence and absence of extracellular Ca2+. In the absence of extracellular Ca2+, depletion of the intracellular Ca2+ stores with either ATP (1 microM) or thapsigargin (100 nM) prevented any further release of Ca2+ on the subsequent addition of okadaic acid. Likewise (in the absence of extracellular Ca2+), a prior release of Ca2+ induced by okadaic acid reduced the magnitude of the response to ATP (1 microM). Taken together these observations indicate that okadaic acid induces Ca2+ release from the agonist-sensitive pool. The okadaic acid-induced Ca2+ release was mimicked by another potent phosphatase inhibitor, calyculin A (10 nM), and also the less potent analogue of okadaic acid, 1-nor-okadone (500 nM). The response to okadaic acid was characterised by a series of asynchronous [Ca2+]c oscillations, which at their peak resulted in 40-100% cells, at any one time, having an elevated [Ca2+]c. The response appeared to propagate between adjacent cells and the elevation of [Ca2+]c appeared initially in the cell periphery. In adherent cells, the release of Ca2+ induced by okadaic acid was found to be dependent upon cell density, as the proportion of cells responding to okadaic acid increased as the cell density increased. The response to okadaic acid was not observed in ECV304 cell suspensions. The data suggest that a kinase activity stimulated either directly or indirectly by cell-cell interactions can lead to the release of Ca2+ from the agonist- and thapsigargin-sensitive intracellular stores.
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Affiliation(s)
- T J Hepworth
- Department of Human Anatomy and Cell Biology, University of Liverpool, UK
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Colliard-Rouiller C, Durand J. Arachidonic acid-induced calcium signalling in human airway smooth muscle cells. RESPIRATION PHYSIOLOGY 1997; 107:263-73. [PMID: 9128907 DOI: 10.1016/s0034-5687(96)02521-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The spatiotemporal distribution of Ca2+ signals evoked by arachidonic acid (AA) was investigated in human bronchial smooth muscle cells (SMC), using the single cell video imaging technique and Fura-2 as a fluorescent dye. Baseline Ca2+ levels were markedly heterogeneous in one and the same cell; the local Ca2 concentration laid between 90 +/- 11 and 215 +/- 18 nM (n = 15). AA (2 mM) induced propagating Ca2+ waves, travelling at a mean velocity of 18 +/- 3 microns/sec (n = 7). Ca2+ signals originated at discrete trigger zones, whose kinetic properties differed from those of neighbouring regions. Ca2+ in the trigger zones rose in two phases, with rates of 9.5 +/- 0.8 and 88 +/- 6 nM/sec (n = 17). A single cell frequently exhibited more than one trigger zones. In some cells, the wave did not reach all regions; such inert zones separated functionally the cell in independently active regions. Some regions presented Ca2+ signals that did not spread to the rest of the cell, forming isolated foci. The spatiotemporal variability of Ca2+ signals evoked by AA could result from the heterogeneity of Ca2+ homeostatic processes.
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Affiliation(s)
- M D Bootman
- Babraham Institute Laboratory of Molecular Signalling, Department of Zoology, University of Cambridge, UK.
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