The estimation of free calcium within synaptosomes and mitochondria with fura-2; comparison to quin-2

Komulainen, Hannu; Bondy, Stephen C.

doi:10.1016/0197-0186(87)90172-0

Cited by 102 publications

(58 citation statements)

References 20 publications

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“…Rats were housed in standard conditions (12-hr light-dark cycle, temperature 21 ± 2'C, and humidity 50 ± 10%), four per cage. After decapitation, 0.9-1.0 g cerebrum (excluding pons, medulla, and the main part ofhippocampus) was dissected out on ice and purified synaptosomes prepared as described in detail elsewhere (Komulainen and Bondy, 1987) by the modified method of Gray and Whittaker (1962) (Dodd et al, 1981). Synaptosomes were suspended in 25 mM Hepes buffer, pH 7.4, containing NaCl 125 mM, KCI 5 mM, NaH2PO.…”

Section: Methodsmentioning

confidence: 99%

“…Free intrasynaptosomal Ca 2 ' was measured using the fluorescent Ca 2 + indicator dye fura-2. Details of the method and characteristics of the dyeloaded synaptosomes are in Komulainen and Bondy ( 1987). Briefly, in order to load synaptosomes with fura-2 ( 150-200 µM concentration).…”

Section: Methodsmentioning

confidence: 99%

“…For calculations of [Ca 2 +],. two other ratios were determined for each fura-2-loaded homogenate (Komulainen and Bondy, 1987): Rmin• the ratio of the fluorescence at zero free Ca 2 +. and Rmax.…”

Section: Methodsmentioning

confidence: 99%

“…The plasma membrane maintains vital ionic gradients and is the main barrier to separate 1 mM extracellular Ca 2 + from 0.1-0.3 µM intracellular Ca 2 + (>3000-fold concentration gradient; Tsien et al, 1982;Hesketh et al, 1983;Berthon et al, 1984;Sistare et al, 1985, Komulainen andBondy, 1987). Ca 2 + is an important messenger in the cell (Rasmussen et al, 1984) and by increasing free intracellular Ca 2 +, organometals might initiate chains of events exciting and finally killing the cell.…”

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confidence: 99%

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Increased free intrasynaptosomal Ca2+ by neurotoxic organometals: Distinctive mechanisms

Komulainen

Bondy

1987

Toxicology and Applied Pharmacology

119

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Increased Free Intrasynaptosomal CaH by Neurotoxic Organometals: Distinetive Mechanisms. KOMULAINEN, H., AND BONDY. S. c. (1987). Toxico/. Appl. Pharmacol. 88,[77][78][79][80][81][82][83][84][85][86] Effects of several alkylmetals on free intrasynaptosomal Ca 2 + concentration, [Ca2+],, were studied in vitro using the fluorescent Ca 2 + indicator fura-2. Neurotoxic alkylmetals methylmercury than TET while dimethyltin and methyl tin were inactive. These results indicate that neurotoxic derivatives of alkylmetals studied increase [Caz+];. This occurs mainly either by nonspecific increase (Met-Hg, TET) ofCa 2 + leakage through the plasma membrane and/or specific interference with the mechanisms regulating Ca 2 + fluxes through the plasma membrane (TEL). '9 1987 Academic Press, Inc.The organometals methylmercury (Met-Hg), triethyllead (TEL) (Seawright et al.. 1984; Walsh and Tilson, 1984), triethyltin (TET), and trimethyltin (TMT) (Reuhl and Cranmer, l 984;Reiter and Ruppert, 1984) are neurotoxic but the underlying biochemical mechanisms causing impaired cell function and neuronal death are not as yet fully established. Trialkyltin and trialkyllead are thought to affect primarily mitochondria and thus energy metabolism of the cell (Aldridge, 1984;Bierkamper and Bassett, 1984). They

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Increased free intrasynaptosomal Ca2+ by neurotoxic organometals: Distinctive mechanisms

Komulainen

Bondy

1987

Toxicology and Applied Pharmacology

119

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“…When used in a synaptosomal preparation, such dyes do not significantly modulate some key parameters such as ATP content and membrane potential BONDY of the synaptosome. Furthermore, the physiological properties of the dye-loaded synaptosome, such as neurotransmitter release and other responses to pharmacological agents, appear to be appropriate (30,31). Limitations of the use of these dyes include:…”

Section: Elevationmentioning

confidence: 99%

Intracellular calcium and neurotoxic events

Bondy

1989

Neurotoxicology and Teratology

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Prevention of chemically induced synaptosomal changes

Bondy

McKee

1990

J of Neuroscience Research

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The ability of altered environmental conditions to modulate some properties of synaptosomes has been studied. Incubation conditions used included the presence of methyl mercury or an organochlorine insecticide: chlordecone. Other adverse chemical conditions during incubation were the absence of calcium salts from the incubation medium or the addition of agents bringing about enhanced oxidative conditions. Synaptosomal parameters studied were the cytosolic level of free, ionic calcium, [Ca2+]i, the extent of depolarization-induced uptake of radioactive calcium, and the permeability of the limiting membrane. In addition, peroxidative activity was estimated by quantitation of thiobarbituric acid-reactive material. All these facets of synaptosomal function were responsive to the presence of these potentially deleterious changes in the incubation medium. While the response of [Ca2+]i was potentially in either direction, all adverse conditions increased synaptosomal permeability as evaluated by leakage of fura-2 into the extracellular compartment. Pretreatment with ganglioside GM1 in some situations or alpha-tocopherol in others could either wholly or partially prevent the onset of such altered synaptosomal characteristics.

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The estimation of free calcium within synaptosomes and mitochondria with fura-2; comparison to quin-2

Cited by 102 publications

References 20 publications

Increased free intrasynaptosomal Ca2+ by neurotoxic organometals: Distinctive mechanisms

Increased free intrasynaptosomal Ca2+ by neurotoxic organometals: Distinctive mechanisms

Intracellular calcium and neurotoxic events

Prevention of chemically induced synaptosomal changes

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