Journal ArticleDOI
Ionic mobility in muscle cells.
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TLDR
The diffusivity of ionic potassium, sodium, sulfate, and adenosine triphosphate inside a nmuscle cell are reduced, relative to diffusivities in aqueous solution, showing that the diffusion of the ions is retarded by physical, rather than chemical, interactions.Abstract:
The diffusivities of ionic potassium, sodium, sulfate, and adenosine triphosphate inside a nmuscle cell are reduced by a factor of 2, relative to diffusivities in aqueous solution. The diffusion coefficients of nonelectrolytes are reduced by the same factor, showing that the diffusion of the ions is retarded by physical, rather than chemical, interactions. In contrast, the diffusivity of the calcium ion, which is taken up by the sarcoplasmic reticulum, is reduced fiftyfold.read more
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Sodium/Calcium Exchange: Its Physiological Implications
TL;DR: In cardiac myocytes, and probably other cell types, the exchanger serves a housekeeping role by maintaining a low intracellular Ca2+ concentration; its possible role in cardiac excitation-contraction coupling is controversial.
Journal ArticleDOI
Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum
TL;DR: The hypothesis of a Ca2 +-induced Ca2+ release (CICR) from the sarcoplasmic reticulum (SR) is supported by experiments done in skinned cardiac cells (sarcolemma removed by microdissection).
Journal ArticleDOI
Range of messenger action of calcium ion and inositol 1,4,5-trisphosphate
TL;DR: For a transient point source of messenger in cells smaller than 20 microns, IP3 is a global messenger, whereas Ca2+ acts in restricted domains.
Journal ArticleDOI
Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum☆
TL;DR: Experiments done in skinned cardiac cells show that CICR is not all or none, and calculations of the Ca2+ buffering in the mammalian ventricular cell and of the systolic transsarcolemmal Ca 2+ influx do not support the alternative hypothesis that this influx of Ca2+, is large enough to activate the myofilaments directly.
References
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Journal ArticleDOI
Localization of calcium-accumulating structures in striated muscle fibers.
TL;DR: When frog muscle fibers from which the sarcolemma had been dissected away were perfused with a calcium solution and then treated with oxalate, electron-opaque material accumulated in the terminal sacs of the sarcoplasmic reticulum, identifying regions of calcium accumulation with the intracellular calcium sink that controls the relaxation phase of the contraction-relaxation cycle.
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Intracellular calcium movements of frog skeletal muscle during recovery from tetanus.
TL;DR: It is proposed that electrical stimulation releases calcium from the terminal cisternae and that relaxation occurs from the binding of the released calcium by the longitudinal tubules and the intermediate cisterna.
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Ion-exchange thin-layer chromatography : XV. Preparation, properties and applications of paper-like pei-cellulose sheets☆
K. Randerath,E. Randerath +1 more
TL;DR: Preparation and properties of anion-exchange (PEI-cellulose) thin layers on plastic sheets are described and techniques for quantitative assays, rechromatography, descending and continous-flow chromatography are reported.
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Time courses of blood gas changes provoked by light and moderate exercise in man.
TL;DR: Changes in arterial gas levels in response to constant-load, dynamic exercise were studied in 8 healthy male subjects by continuous analyses of arterial pH and O2 saturation and the shift towards acidosis during exercise was roughly proportional to the relative intensity of work.
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NMR Evidence for Complexing of Na+ in Muscle, Kidney, and Brain, and by Actomyosin. The Relation of Cellular Complexing of Na+ to Water Structure and to Transport Kinetics
TL;DR: NMR studies show that Na+ is complexed by actomyosin, which may be the molecular site of complexation of some Na+ in muscle, which suggests that the water in the gel is organized into an icelike state by the nearby actomyOSin molecules.