The control of ionized calcium in squid axons.
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چکیده
منابع مشابه
The control of ionized calcium in squid axons
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...
متن کاملIonized 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...
متن کاملIonized magnesium concentration in axoplasm of dialyzed squid axons.
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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Squid giant axons injected with either aequorin or arsenazo III and bathed in 3 mM Ca (Na) seawater were transferred to 3 mM Ca (K) seawater and the response of the aequorin light or the change in the absorbance of arsenazo III was followed. These experimental conditions were chosen because they measure the change in the rate of Na/Ca exchange in introducing Ca into the axon upon depolarization...
متن کاملIntracellular calcium buffering capacity in isolated squid axons
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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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1977
ISSN: 0022-1295,1540-7748
DOI: 10.1085/jgp.70.3.329