Ionized calcium concentrations in squid axons.
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چکیده
منابع مشابه
Ionized calcium concentrations in squid axons
Values for ionized [Ca] in squid axons were obtained by measuring the light emission from a 0.1-mul drop of aequorin confined to a plastic dialysis tube of 140-mum diameter located axially. Ionized Ca had a mean value of 20 x 10(-9) M as judged by the subsequent introduction of CaEGTA/EGTA buffer (ratio ca. 0.1) into the axoplasm, and light measurement on a second aequorin drop. Ionized Ca in a...
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Measurements of the Ca content, [Ca](T), of freshly isolated squid axons show a value of 60 mumol/kg axoplasm. Axons in 3 mM Ca(Na) seawater show little change in Ca content over 4 h, while axons in 3 mM Ca(Na) seawater show little change in Ca content over 4 h, while axons in 10 mM Ca(Na) seawater show gains of 18 mumol/Ca/kgxh. In 10 Ca (Choline) seawater the gain is 2,400 mumol/kgxh. Using a...
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Magnesium ion is a significant constituent of cell cytoplasm and participates in many intracellular enzymatic reactions. Although total cell magnesium can be rather easily determined by atomic absorption spectroscopy, the free magnesium is more difficult to measure and is much less than the total because of magnesium binding to cellular organelles or ionic constituents. Moreover, since magnesiu...
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Changes in ionized calcium were studied in axons isolated from living squid by measuring absorbance of the Ca binding dye Arsenazo III using multiwavelength differential absorption spectroscopy. Absorption changes measured in situ were calibrated in vitro with media of ionic composition similar to axoplasm containing CaEGTA buffers. Calcium loads of 50-2,500 mumol/kg axoplasm were induced by mi...
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Axons freshly dissected from living specimens of the tropical squid Dorytheutis plei have a calcium content of 68 tzmol/kg of axoplasm. Fibers stimulated at 100 impuises/s in 100 mM Ca seawater increase their Ca content by 150/zmol/ kg.min; axons placed in 3 Ca (choline) seawater increase their Ca content by 12 /zmol/kg.min. Axons loaded with 0.2-1.5 mmol Ca/kg of axoplasm extruded Ca with a ha...
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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1976
ISSN: 0022-1295,1540-7748
DOI: 10.1085/jgp.67.4.433