Elementary and global aspects of calcium signalling.
TLDR
Using Ca2+ imaging techniques, the opening of individual channels has now been visualized and models have been proposed to explain how these elementary events are coordinated to generate the global Ca 2+ signals that regulate cellular activity.Abstract:
Calcium is a ubiquitous second messenger used to regulate a wide range of cellular processes. This role in signalling has to be conducted against the rigid homeostatic mechanisms that ensure that the resting level of Ca2+ is kept low (i.e. between 20 and 100 nmol l-1) in order to avoid the cytotoxic effects of a prolonged elevation of [Ca2+]. Cells have evolved a sophisticated signalling system based on the generation of brief pulses of Ca2+ which enables this ion to be used as a messenger, thus avoiding its toxic effects. Such Ca2+ spikes usually result from the coordinated release of Ca2+ from internal stores using either inositol 1,4,5-trisphosphate or ryanodine receptors. Using Ca2+ imaging techniques, the opening of individual channels has now been visualized and models have been proposed to explain how these elementary events are coordinated to generate the global Ca2+ signals that regulate cellular activity.read more
Citations
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Ca2+ signaling in mouse cortical neurons studied by two-photon imaging and photoreleased inositol triphosphate.
TL;DR: IP3-mediated Ca2+ signals strongly inhibited spike firing through activation of K+ membrane conductance and serves as a powerful and sustained modulator of excitability in cortical neurons and displays complex reciprocal interactions between electrical and chemical signals.
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Molecular Cloning of Mouse Type 2 and Type 3 Inositol 1,4,5-Trisphosphate Receptors and Identification of a Novel Type 2 Receptor Splice Variant
Miwako Iwai,Yoko Tateishi,Mitsuharu Hattori,Akihiro Mizutani,Takeshi Nakamura,Akira Futatsugi,Takafumi Inoue,Teiichi Furuichi,Takayuki Michikawa,Katsuhiko Mikoshiba +9 more
TL;DR: Encoding of cDNAs encoding type 2 and type 3 inositol 1,4,5-trisphosphate (IP3) receptors was isolated from mouse lung and a novel alternative splicing segment, SIm2, was found, suggesting that the novel splice variant of IP3R2 specifically influences the dynamics of the sustained phase of Ca2+ signals.
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Stretch-induced Calcium Release in Smooth Muscle
TL;DR: It is reported here that elongation of smooth muscle cells results in ryanodine receptor–mediated Ca2+ release in individual myocytes, suggesting a regulatory mechanism for the generation of spontaneous currents in smooth muscle.
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Role of phospholamban in the modulation of arterial Ca2+ sparks and Ca2+-activated K+ channels by cAMP
TL;DR: This study provides the first evidence that PLB is critical for frequency modulation of Ca(2+) sparks and associated BK currents by PKA in smooth muscle.
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The structure and function of the cardiac myocyte: a review of fundamental concepts.
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References
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Journal ArticleDOI
Inositol trisphosphate and calcium signalling
TL;DR: Inositol trisphosphate is a second messenger that controls many cellular processes by generating internal calcium signals through receptors whose molecular and physiological properties closely resemble the calcium-mobilizing ryanodine receptors of muscle.
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Inositol trisphosphate, a novel second messenger in cellular signal transduction.
TL;DR: Diacylglycerol operates within the plane of the membrane to activate protein kinase C, whereas inositol trisphosphate is released into the cytoplasm to function as a second messenger for mobilizing intracellular calcium.
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A model for receptor-regulated calcium entry
TL;DR: A capacitative model is proposed for the mechanism by which activation of surface membrane receptors causes sustained Ca2+ entry into cells from the extracellular space, which allows forCa2+ release and Ca2-mobilization to be controlled by a single messenger, inositol (1,4,5) trisphosphate.
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Release of Ca2+ from a nonmitochondrial intracellular store in pancreatic acinar cells by inositol-1,4,5-trisphosphate.
TL;DR: It is reported here that micromolar concentrations of Ins1,4,5P3 release Ca2+ from a nonmitochondrial intracellular Ca2- store in pancreatic acinar cells, and the results strongly suggest that this is the same Ca1+ store that is released by acetylcholine.
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Calcium sparks: elementary events underlying excitation-contraction coupling in heart muscle
TL;DR: The calcium spark is the consequence of elementary events underlying excitation-contraction coupling and provides an explanation for both spontaneous and triggered changes in the intracellular calcium concentration in the mammalian heart.