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Gerbino A, Colella M. The Different Facets of Extracellular Calcium Sensors: Old and New Concepts in Calcium-Sensing Receptor Signalling and Pharmacology. Int J Mol Sci 2018; 19:E999. [PMID: 29584660 PMCID: PMC5979557 DOI: 10.3390/ijms19040999] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 03/23/2018] [Accepted: 03/25/2018] [Indexed: 12/14/2022] Open
Abstract
The current interest of the scientific community for research in the field of calcium sensing in general and on the calcium-sensing Receptor (CaR) in particular is demonstrated by the still increasing number of papers published on this topic. The extracellular calcium-sensing receptor is the best-known G-protein-coupled receptor (GPCR) able to sense external Ca2+ changes. Widely recognized as a fundamental player in systemic Ca2+ homeostasis, the CaR is ubiquitously expressed in the human body where it activates multiple signalling pathways. In this review, old and new notions regarding the mechanisms by which extracellular Ca2+ microdomains are created and the tools available to measure them are analyzed. After a survey of the main signalling pathways triggered by the CaR, a special attention is reserved for the emerging concepts regarding CaR function in the heart, CaR trafficking and pharmacology. Finally, an overview on other Ca2+ sensors is provided.
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Affiliation(s)
- Andrea Gerbino
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70121 Bari, Italy.
| | - Matilde Colella
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70121 Bari, Italy.
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Colella M, Gerbino A, Hofer AM, Curci S. Recent advances in understanding the extracellular calcium-sensing receptor. F1000Res 2016; 5. [PMID: 27803801 PMCID: PMC5074356 DOI: 10.12688/f1000research.8963.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/13/2016] [Indexed: 12/11/2022] Open
Abstract
The extracellular calcium-sensing receptor (CaR), a ubiquitous class C G-protein-coupled receptor (GPCR), is responsible for the control of calcium homeostasis in body fluids. It integrates information about external Ca
2+ and a surfeit of other endogenous ligands into multiple intracellular signals, but how is this achieved? This review will focus on some of the exciting concepts in CaR signaling and pharmacology that have emerged in the last few years.
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Affiliation(s)
- Matilde Colella
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari , Bari, Italy
| | - Andrea Gerbino
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari , Bari, Italy
| | - Aldebaran M Hofer
- Department of Surgery, Brigham & Women's Hospital, Harvard Medical School and VA Boston Healthcare System, West Roxbury, MA, USA
| | - Silvana Curci
- Department of Surgery, Brigham & Women's Hospital, Harvard Medical School and VA Boston Healthcare System, West Roxbury, MA, USA
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McNally JM, Custer EE, Ortiz-Miranda S, Woodbury DJ, Kraner SD, Salzberg BM, Lemos JR. Functional ryanodine receptors in the membranes of neurohypophysial secretory granules. ACTA ACUST UNITED AC 2014; 143:693-702. [PMID: 24863930 PMCID: PMC4035742 DOI: 10.1085/jgp.201311110] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Highly localized Ca(2+) release events have been characterized in several neuronal preparations. In mouse neurohypophysial terminals (NHTs), such events, called Ca(2+) syntillas, appear to emanate from a ryanodine-sensitive intracellular Ca(2+) pool. Traditional sources of intracellular Ca(2+) appear to be lacking in NHTs. Thus, we have tested the hypothesis that large dense core vesicles (LDCVs), which contain a substantial amount of calcium, represent the source of these syntillas. Here, using fluorescence immunolabeling and immunogold-labeled electron micrographs of NHTs, we show that type 2 ryanodine receptors (RyRs) are localized specifically to LDCVs. Furthermore, a large conductance nonspecific cation channel, which was identified previously in the vesicle membrane and has biophysical properties similar to that of an RyR, is pharmacologically affected in a manner characteristic of an RyR: it is activated in the presence of the RyR agonist ryanodine (at low concentrations) and blocked by the RyR antagonist ruthenium red. Additionally, neuropeptide release experiments show that these same RyR agonists and antagonists modulate Ca(2+)-elicited neuropeptide release from permeabilized NHTs. Furthermore, amperometric recording of spontaneous release events from artificial transmitter-loaded terminals corroborated these ryanodine effects. Collectively, our findings suggest that RyR-dependent syntillas could represent mobilization of Ca(2+) from vesicular stores. Such localized vesicular Ca(2+) release events at the precise location of exocytosis could provide a Ca(2+) amplification mechanism capable of modulating neuropeptide release physiologically.
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Affiliation(s)
- James M McNally
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655
| | - Edward E Custer
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655
| | - Sonia Ortiz-Miranda
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655
| | - Dixon J Woodbury
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602
| | - Susan D Kraner
- Department of Neuroscience and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Brian M Salzberg
- Department of Neuroscience and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104 Department of Neuroscience and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - José R Lemos
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655
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Gerbino A, Maiellaro I, Carmone C, Caroppo R, Debellis L, Barile M, Busco G, Colella M. Glucose increases extracellular [Ca2+] in rat insulinoma (INS-1E) pseudoislets as measured with Ca2+-sensitive microelectrodes. Cell Calcium 2012; 51:393-401. [PMID: 22361140 DOI: 10.1016/j.ceca.2012.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 12/29/2011] [Accepted: 01/08/2012] [Indexed: 11/24/2022]
Abstract
Secretory granules of pancreatic β-cells contain high concentrations of Ca2+ ions that are co-released with insulin in the extracellular milieu upon activation of exocytosis. As a consequence, an increase in the extracellular Ca2+ concentration ([Ca2+]ext) in the microenvironment immediately surrounding β-cells should be expected following the exocytotic event. Using Ca2+-selective microelectrodes we show here that both high glucose and non-nutrient insulinotropic agents elicit a reversible increase of [Ca2+]ext within rat insulinoma (INS-1E) β-cells pseudoislets. The glucose-induced increases in [Ca2+]ext are blocked by pretreatment with different Ca2+ channel blockers. Physiological agonists acting as positive or negative modulators of the insulin secretion and drugs known to intersect the secretory machinery at different levels also induce [Ca2+]ext changes as predicted on the basis of their described action on insulin secretion. Finally, the glucose-induced [Ca2+]ext increase is strongly inhibited after disruption of the actin web, indicating that the dynamic [Ca2+]ext changes recorded in INS-1E pseudoislets by Ca2+-selective microelectrodes occur mainly as a consequence of exocytosis of Ca2+-rich granules. In conclusion, our data directly demonstrate that the extracellular spaces surrounding β-cells constitute a restricted domain where Ca2+ is co-released during insulin exocytosis, creating the basis for an autocrine/paracrine cell-to-cell communication system via extracellular Ca2+ sensors.
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Affiliation(s)
- Andrea Gerbino
- Department of Biosciences, Biotechnology and Pharmacological Sciences, University of Bari, Via G. Amendola 165/A, 70126 Bari, Italy.
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Kachoei BA, Knox RJ, Uthuza D, Levy S, Kaczmarek LK, Magoski NS. A store-operated Ca(2+) influx pathway in the bag cell neurons of Aplysia. J Neurophysiol 2006; 96:2688-98. [PMID: 16885525 PMCID: PMC2894935 DOI: 10.1152/jn.00118.2006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although store-operated Ca(2+) influx has been well-studied in nonneuronal cells, an understanding of its nature in neurons remains poor. In the bag cell neurons of Aplysia californica, prior work has suggested that a Ca(2+) entry pathway can be activated by Ca(2+) store depletion. Using fura-based imaging of intracellular Ca(2+) in cultured bag cell neurons, we now characterize this pathway as store-operated Ca(2+) influx. In the absence of extracellular Ca(2+), the endoplasmic reticulum Ca(2+)-ATPase inhibitors, cyclopiazonic acid (CPA) or thapsigargin, depleted intracellular stores and elevated intracellular free Ca(2+). With the subsequent addition of extracellular Ca(2+), a prominent Ca(2+) influx was observed. The ryanodine receptor agonist, chloroethylphenol (CEP), also increased intracellular Ca(2+) but did not initiate store-operated Ca(2+) influx, despite overlap between CEP- and CPA-sensitive stores. Bafilomycin A, a vesicular H(+)-ATPase inhibitor, liberated intracellular Ca(2+) from acidic stores and attenuated subsequent Ca(2+) influx, presumably by replenishing CPA-depleted stores. Store-operated Ca(2+) influx was partially blocked by low concentrations of La(3+) or BTP2, and strongly inhibited by either 1-[b-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole (SKF-96365) or a high concentration of Ni(2+). Regarding IP(3) receptor blockers, 2-aminoethyldiphenyl borate, but not xestospongin C, prevented store-operated Ca(2+) influx. However, jasplakinolide, an actin stabilizer reported to inhibit this pathway in smooth muscle cell lines, was ineffective. The bag cell neurons initiate reproductive behavior through a prolonged afterdischarge associated with intracellular Ca(2+) release and neuropeptide secretion. Store-operated Ca(2+) influx may serve to replenish stores depleted during the afterdischarge or participate in the release of peptide that triggers behavior.
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Affiliation(s)
- Babak A Kachoei
- Department of Physiology, Queen's University, 4th Floor, Botterell Hall, 18 Stuart St., Kingston, ON, K7L 3N6, Canada
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Gerasimenko JV, Sherwood M, Tepikin AV, Petersen OH, Gerasimenko OV. NAADP, cADPR and IP3 all release Ca2+ from the endoplasmic reticulum and an acidic store in the secretory granule area. J Cell Sci 2006; 119:226-38. [PMID: 16410548 DOI: 10.1242/jcs.02721] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Inositol trisphosphate and cyclic ADP-ribose release Ca2+ from the endoplasmic reticulum via inositol trisphosphate and ryanodine receptors, respectively. By contrast, nicotinic acid adenine dinucleotide phosphate may activate a novel Ca2+ channel in an acid compartment. We show, in two-photon permeabilized pancreatic acinar cells, that the three messengers tested could each release Ca2+ from the endoplasmic reticulum and also from an acid store in the granular region. The nicotinic acid adenine dinucleotide phosphate action on both types of store, like that of cyclic ADP-ribose but unlike inositol trisphosphate, depended on operational ryanodine receptors, since it was blocked by ryanodine or ruthenium red. The acid Ca2+ store in the granular region did not have Golgi or lysosomal characteristics and might therefore be associated with the secretory granules. The endoplasmic reticulum is predominantly basal, but thin extensions penetrate into the granular area and cytosolic Ca2+ signals probably initiate at sites where endoplasmic reticulum elements and granules come close together.
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Affiliation(s)
- Julia V Gerasimenko
- MRC Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK.
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Torrealba F, Carrasco MA. A review on electron microscopy and neurotransmitter systems. ACTA ACUST UNITED AC 2005; 47:5-17. [PMID: 15572159 DOI: 10.1016/j.brainresrev.2004.06.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2004] [Indexed: 10/26/2022]
Abstract
The purpose of this article is to review the contributions of transmission electron microscopy studies to the understanding of brain circuits and neurotransmitter systems. Our views on the microstructure of connections between neurons have gradually changed, and now we recognize that the classical mental image we had on a chemical synapse is no longer applicable to every neuronal connection. We highlight studies that converge to point out that, while the most prevalent fast transmitters in the brain, glutamate and GABA, are stored in small, clear synaptic vesicles (SSV) and released at synapses, neuropeptides are exclusively stored in large dense core vesicles (LDCV) and released extrasynaptically. Amine transmitters are preferentially, but not exclusively, accumulated in LDCV and may be released at synaptic or extrasynaptic sites. We discuss evidence suggesting that axon terminals from pyramidal cortical neurons and dorsal thalamic neurons lack LDCV and therefore could not use neuropeptides as transmitters. This idea fits with the fast, high temporal resolution information processing that characterizes cortical and thalamic function.
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Affiliation(s)
- Fernando Torrealba
- Departamento de Ciencias Fisiológicas, Fac. Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
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De Crescenzo V, ZhuGe R, Velázquez-Marrero C, Lifshitz LM, Custer E, Carmichael J, Lai FA, Tuft RA, Fogarty KE, Lemos JR, Walsh JV. Ca2+ syntillas, miniature Ca2+ release events in terminals of hypothalamic neurons, are increased in frequency by depolarization in the absence of Ca2+ influx. J Neurosci 2004; 24:1226-35. [PMID: 14762141 PMCID: PMC6793580 DOI: 10.1523/jneurosci.4286-03.2004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2003] [Revised: 12/09/2003] [Accepted: 12/11/2003] [Indexed: 11/21/2022] Open
Abstract
Localized, brief Ca2+ transients (Ca2+ syntillas) caused by release from intracellular stores were found in isolated nerve terminals from magnocellular hypothalamic neurons and examined quantitatively using a signal mass approach to Ca2+ imaging. Ca2+ syntillas (scintilla, L., spark, from a synaptic structure, a nerve terminal) are caused by release of approximately 250,000 Ca ions on average by a Ca2+ flux lasting on the order of tens of milliseconds and occur spontaneously at a membrane potential of -80 mV. Syntillas are unaffected by removal of extracellular Ca2+, are mediated by ryanodine receptors (RyRs) and are increased in frequency, in the absence of extracellular Ca2+, by physiological levels of depolarization. This represents the first direct demonstration of mobilization of Ca2+ from intracellular stores in neurons by depolarization without Ca2+ influx. The regulation of syntillas by depolarization provides a new link between neuronal activity and cytosolic [Ca2+] in nerve terminals.
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Affiliation(s)
- Valérie De Crescenzo
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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Raison S, Gillot I, Choine C, Pistone P, Pagnotta S, Laugier JP, Nicaise G. Ca increase in secretory granules of stimulated mast cells. Cell Calcium 1999; 26:111-9. [PMID: 10598275 DOI: 10.1054/ceca.1999.0062] [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: 11/18/2022]
Abstract
The elemental content of rat peritoneal mast-cell secretory granules has been measured by X-ray micro-analysis. Two distinct categories of granules were analyzed: intact granules, seen in control samples, and spumous granules, corresponding to exocytosed granule matrices. The average Ca content of intact granules was found to be approximately equal to cytosolic concentration, and to increase up to 40-fold in spumous granules. A significant increase was also observed for Na and Cl. These changes were not observed (for Ca) or weaker (for Na and Cl) if the cells had been challenged in the absence of nominal extracellular Ca; in this case, there was also a significant decrease in the sulphur content, suggesting a partial dispersion of the organic matrix components. In exocytosed granule matrices, in the presence but not in the absence of extracellular Ca, a slow and long-lasting increase of intragranular free Ca was monitored by changes in the fluorescence of the Ca-sensitive probes Fluo-3 and Calcium Green-5N, accumulated within rat mast-cell secretory granules. These findings are discussed along two lines: It is proposed that the calcium uptake by the exocytosed mast-cell granule matrices can have a physiological relevance for the surrounding tissue. Mast-cell granules do not disperse after exocytosis. The major uptake of Ca which is seen after opening of the exocytotic pore could be responsible for the exceptional stability of the externalized matrices.
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Affiliation(s)
- S Raison
- Faculté des Sciences, Université de Nice-Sophia Antipolis, France
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Thirion S, Troadec JD, Pivovarova NB, Pagnotta S, Andrews SB, Leapman RD, Nicaise G. Stimulus-secretion coupling in neurohypophysial nerve endings: a role for intravesicular sodium? Proc Natl Acad Sci U S A 1999; 96:3206-10. [PMID: 10077662 PMCID: PMC15920 DOI: 10.1073/pnas.96.6.3206] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is generally accepted that Ca is essentially involved in regulated secretion, but the role of this cation, as well as others such as Na, is not well understood. An illustrative example occurs in neurohypophysial secretion, where an experimentally induced increase in the cytosolic concentration of Na+ can induce continuous neuropeptide release. In contrast, an increase in cytosolic Ca2+ will have only a transient stimulatory effect. The secretion-promoting targets for Ca2+ are not known; they may be cytosolic, as is usually assumed, but they may also be intravesicular, especially in view of evidence that Ca-rich secretory vesicles are preferentially secreted. In the present work, we have investigated the movements of these cations into and out of secretory vesicles during stimulus-secretion coupling. Isolated rat neurohypophysial nerve endings were stimulated by potassium (55 mM) depolarization, and at 6 min (peak secretion) and 20 min after the onset of stimulation, the elemental content of individual secretory vesicles was measured by quantitative x-ray microanalysis. A depolarization-induced transient increase in intravesicular Na+ concentration was found to coincide with the onset of secretion. Moreover, only a predicted small fraction of peripheral vesicles-presumably the docked ones-were Na+-loaded. The low sulfur concentration of Na+-rich vesicles most likely resulted from vesicle swelling. The results suggest that high intravesicular Na+ concentrations in docked vesicles, occurring by Na+/Ca2+ exchange or by transient fusion pore opening, is a proximal event in exocytosis.
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Affiliation(s)
- S Thirion
- Laboratoire de Physiologie Cellulaire et Moléculaire, and Centre Commun de Microscopie Appliquée, Faculté des Sciences, Université de Nice-Sophia Antipolis, 06108 Nice, France
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Scheenen WJ, Wollheim CB, Pozzan T, Fasolato C. Ca2+ depletion from granules inhibits exocytosis. A study with insulin-secreting cells. J Biol Chem 1998; 273:19002-8. [PMID: 9668080 DOI: 10.1074/jbc.273.30.19002] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The secretory compartment is characterized by low luminal pH and high Ca2+ content. Previous studies in several cell types have shown that the size of the acidic Ca2+ pool, of which secretory granules represent a major portion, could be estimated by applying first a Ca2+ ionophore followed by agents that collapse acidic pH gradients. In the present study we have employed this protocol in the insulin-secreting cell line Ins-1 to determine whether the Ca2+ trapped in the secretory granules plays a role in exocytosis. The results demonstrate that a high proportion of ionophore-mobilizable Ca2+ in Ins-1 cells resides in the acidic compartment. The latter pool, however, does not significantly contribute to the [Ca2+]i changes elicited by thapsigargin and the inositol trisphosphate-producing agonist carbachol. By monitoring membrane capacitance at the single cell level or by measuring insulin release in cell populations, we show that Ca2+ mobilization from nonacidic Ca2+ pools causes a profound and long lasting increase in depolarization-induced secretion, whereas breakdown of granule pH had no significant effect. In contrast, releasing Ca2+ from the acidic pool markedly reduces secretion. It is suggested that a high Ca2+ concentration in the secretory compartment is needed to sustain optimal exocytosis.
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Affiliation(s)
- W J Scheenen
- Department of Biomedical Sciences, Consiglio Nazionale delle Ricerche, Center of Biomembranes, University of Padova, Via G. Colombo 3, 35100 Padova Italy.
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Belan P, Gardner J, Gerasimenko O, Gerasimenko J, Mills CL, Petersen OH, Tepikin AV. Isoproterenol Evokes Extracellular Ca2+ Spikes Due to Secretory Events in Salivary Gland Cells. J Biol Chem 1998. [DOI: 10.1074/jbc.273.7.4106] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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