Rapid, stimulation-induced reduction of C12-resorufin in motor nerve terminals: linkage to mitochondrial metabolism.
J Neurochem
; 105(3): 807-19, 2008 May.
Article
in En
| MEDLINE
| ID: mdl-18205748
ABSTRACT
The Alamar blue (resazurin) assay of cell viability monitors the irreversible reduction of non-fluorescent resazurin to fluorescent resorufin. This study focused on the reversible reduction of C12-resorufin to non-fluorescent C12-dihydroresorufin in motor nerve terminals innervating lizard intercostal muscles. Resting C12-resorufin fluorescence decreased when the activity of the mitochondrial electron transport chain (ETC) was accelerated with carbonyl cyanide m-chloro phenyl hydrazone, and increased when ETC activity was inhibited with cyanide. Trains of action potentials (50 Hz for 20-50 s), which reversibly decreased NADH fluorescence and partially depolarized the mitochondrial membrane potential, produced a reversible decrease in C12-resorufin fluorescence which had a similar time course. The stimulation-induced decrease in C12-resorufin fluorescence was blocked by inhibitors of ETC complexes I, III, and IV and by carbonyl cyanide m-chloro phenyl hydrazone, but not by inhibiting mitochondrial ATP synthesis with oligomycin. Mitochondrial depolarization and the decreases in C12-resorufin and NADH fluorescence depended on Ca2+ influx into the terminal, but not on vesicular transmitter release. These results suggest that the reversible reduction of C12-resorufin in stimulated motor nerve terminals is linked, directly or indirectly, to the reversible oxidation of NADH and to Ca(2+) influx into mitochondria, and provides an assay for rapid changes in motor terminal metabolism.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Oxazines
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Presynaptic Terminals
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Energy Metabolism
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Mitochondria
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Motor Neurons
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Neuromuscular Junction
Limits:
Animals
Language:
En
Journal:
J Neurochem
Year:
2008
Document type:
Article
Affiliation country:
United States