ATP-stimulated accumulation of calcium by chromaffin granules and mitochondria from the adrenal medulla

Grafenstein, H.R.K. Von; Neumann, Eberhard

doi:10.1016/0006-291x(83)91567-x

Cited by 14 publications

(3 citation statements)

References 10 publications

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“…Calcium uptake by CGs has not been well defined, although several groups have studied it (Kostron et al, 1977;Hausler et al, 1981;Phillips, 1981;Krieger-Brauer and Gratzl, 1982;Grafenstein and Neumann, 1983). Two mechanisms have been proposed for the uptake by CGs: ATP-stimulated calcium uptake, which presumably depends on the proton gradient across the granular membrane; and Na+/Ca2' exchange.…”

Section: Discussionmentioning

confidence: 99%

Calcium Homeostasis in Digitonin‐Permeabilized Bovine Chromaffin Cells

Kao

1988

Journal of Neurochemistry

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The regulation of cytosolic calcium was studied in digitonin-permeabilized chromaffin cells. Accumulation of 45Ca2+ by permeabilized cells was measured at various Ca2+ concentrations in the incubation solutions. In the absence of ATP, there was a small (10-15% of total uptake) but significant increase in accumulation of Ca2+ into both the vesicular and nonvesicular pools. In the presence of ATP, the permeabilized cells accumulated Ca2+ into carbonyl cyanide m-chlorophenyl hydrazone (CCCP)-sensitive and -insensitive pools. The CCCP-sensitive pool--mainly mitochondria--was active when the calcium concentration was greater than 1 microM and was not saturated at 25 microM. The Ca2+ sequestered by the CCCP-insensitive pool could be inhibited by vanadate and released by inositol trisphosphate, a combination suggesting that this pool was the endoplasmic reticulum. The CCCP-insensitive pool had a high affinity for calcium, with an EC50 of approximately 1 microM. When the Ca2+ concentration was adjusted to the level in the cytoplasm of resting cells (0.1 microM), the presumed endoplasmic reticulum pool was responsible for approximately 90% of the ATP-stimulated calcium uptake. At a calcium level similar to the acetylcholine-stimulated level in intact cells (5-10 microM), most of the Ca2+ (greater than 95%) went into the CCCP-sensitive pool.

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Section: Discussionmentioning

confidence: 99%

Calcium Homeostasis in Digitonin‐Permeabilized Bovine Chromaffin Cells

Kao

1988

Journal of Neurochemistry

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“…All cells were washed and secretion was stimulated with 1 0-4 M carbamylcholine for 15 min and 45Ca uptake was stimulated with the same concentration of carbamylcholine for 10 min using the same specific activity as was used for loading (10 pCi/ ml, 1. cells and does not exclude the possibility that Ca entry into chromaffin granules is accelerated during stimulation as the cytoplasmic level of Ca2+ rises. It has been suggested (e.g., von Grafenstein and Neumann, 1983) that Ca entering the cell during stimulation is taken up by chromaffin granules and exported from the cell during a second secretory cycle. To quantify this pathway of Ca turnover, we stimulated cells with carbamylcholine for a short time to increase uptake of 45Ca, and after a brief washing period we monitored export of 45Ca during a second round of triggered secretion.…”

Section: Time Course Of Entry Of 45ca Into the Releasable Poolmentioning

confidence: 99%

“…(2) Exchange of 45Ca with Na in mature chromaffin granules (Phillips, 198 1 ;Gratzl, 1982, 1983). (3) ATP-stimulated uptake into mature or immature chromaffin granules (Hausler et al, 198 1 ;Niedermaier and Burger, 198 1 ;von Grafenstein and Neumann, 1983). (4) Incorporation of 45Ca into chromaffin granules during their biosynthesis (Winkler, 1977).…”

Section: Entry Of 45ca Into the Releasable Poolmentioning

confidence: 99%

Calcium Is Released by Exocytosis Together with Catecholamines from Bovine Adrenal Medullary Cells

Grafenstein

Powis

1989

Journal of Neurochemistry

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We have tested the hypothesis that exocytosis is a possible export route for calcium from bovine adrenal medullary cells. After prelabelling cells in primary tissue culture with 45Ca, evoked 45Ca export and catecholamine secretion show the same time course, a similar fraction of the total pool of 45Ca and catecholamine is released, and the same concentrations of carbamylcholine or KCl are required for half-maximal triggered release. Increasing the osmolarity of the extracellular medium or treating the cells with botulinum toxin type D inhibits both evoked catecholamine secretion and 45Ca export to the same extent without inhibiting 45Ca influx. Incorporation of 45Ca into chromaffin granules is very slow, however, and incorporated 45Ca is not immediately releasable. 45Ca entering the cell during short-term stimulation is not found in the releasable pool during a second period of triggered secretion. Our data suggest that chromaffin granules are the largest pool of intracellular calcium in bovine adrenal medullary cells and that most of the calcium in chromaffin granules does not rapidly exchange with cytoplasmic Ca, but can be released directly by exocytosis. Exocytosis does not appear to play a major role in exporting Ca that enters the cell during short-term stimulation.

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Transport and Storage of Catecholamines in Vesicles

Philippu¹,

Matthaei²

1988

Handbook of Experimental Pharmacology

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ATP-stimulated accumulation of calcium by chromaffin granules and mitochondria from the adrenal medulla

Cited by 14 publications

References 10 publications

Calcium Homeostasis in Digitonin‐Permeabilized Bovine Chromaffin Cells

Calcium Homeostasis in Digitonin‐Permeabilized Bovine Chromaffin Cells

Calcium Is Released by Exocytosis Together with Catecholamines from Bovine Adrenal Medullary Cells

Transport and Storage of Catecholamines in Vesicles

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