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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
23
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pubmed:dateCreated |
1997-12-15
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pubmed:abstractText |
Stimulus-secretion coupling was monitored with capacitance detection in bovine chromaffin cells recorded in perforated patch mode and stimulated with trains of depolarizing pulses. A subset of stimulus trains evoked a response with a Ca2+-exocytosis relationship identical to that obtained for single depolarizing pulses (Engisch and Nowycky, 1996). Other trains evoked responses with enhanced or diminished Ca2+ efficacy relative to this input-output function. The probability of obtaining a particular Ca2+-exocytosis relationship was correlated with the amount of Ca2+ entry per pulse, such that shorter pulses or smaller currents were associated with the greatest efficacy, and longer pulses and larger currents with the lowest efficacy. Apparent enhancements in Ca2+ efficacy were not caused by residual Ca2+ summing between pulses, because decreasing the interval between pulses usually reduced efficacy in the same cell; conversely, increasing the interval between pulses did not prevent an enhanced Ca2+-exocytosis relationship. Apparent decreases in Ca2+ efficacy were not caused by depletion of an available pool of release-ready vesicles, because an equivalent amount of total Ca2+ entry during a single long depolarizing pulse usually evoked a much larger secretory response in the same cell. Finally, there were no striking differences in global Ca2+ levels monitored with the fluorescent indicator Fura Red that could account for apparent changes in Ca2+ efficacy during repetitive stimulus protocols. It appears that in chromaffin cells, the Ca2+-exocytosis relationship is subject to activity-dependent changes during a stimulus train and can be modulated up or down from a basal state accessed by single pulse stimulations.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Dec
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pubmed:issn |
0270-6474
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
17
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
9010-25
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:9364048-Action Potentials,
pubmed-meshheading:9364048-Adrenal Medulla,
pubmed-meshheading:9364048-Animals,
pubmed-meshheading:9364048-Calcium,
pubmed-meshheading:9364048-Calcium Channels,
pubmed-meshheading:9364048-Catecholamines,
pubmed-meshheading:9364048-Cattle,
pubmed-meshheading:9364048-Cells, Cultured,
pubmed-meshheading:9364048-Chromaffin Cells,
pubmed-meshheading:9364048-Electric Conductivity,
pubmed-meshheading:9364048-Electric Stimulation,
pubmed-meshheading:9364048-Exocytosis,
pubmed-meshheading:9364048-Ion Channel Gating,
pubmed-meshheading:9364048-Ion Transport,
pubmed-meshheading:9364048-Patch-Clamp Techniques
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pubmed:year |
1997
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pubmed:articleTitle |
Short-term changes in the Ca2+-exocytosis relationship during repetitive pulse protocols in bovine adrenal chromaffin cells.
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pubmed:affiliation |
Department of Neurobiology and Anatomy, Medical College of Pennsylvania-Hahnemann University, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania 19129, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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