Ca(2+)-independent release of glutamate during in vitro anoxia in isolated nerve terminals.
The effects of in vitro anoxia on the release of glutamate in isolated nerve terminals were studied. The extra-synaptosomal concentration of glutamate ([Glu]ext) under aerobic conditions was 2.3 microM and increased to 4.9 microM after 10 min of anoxia. However, when synaptosomes were incubated in the presence of lactate plus pyruvate instead of glucose, to prevent anaerobic glycolysis, anoxia induced an eightfold increase in the [Glu]ext. The accumulation of glutamate in the external medium during anoxia was Ca2+ independent and insensitive to a significant reduction of the Ca(2+)-dependent release of the amino acid. These results indicate that a Ca(2+)-independent efflux of cytoplasmic glutamate occurs during in vitro anoxia in isolated nerve terminals.
Rubio
I
I
Departamento de Bioquímica, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
Torres
M
M
Miras-Portugal
M T
MT
Sánchez-Prieto
J
J
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D008297:Male; D009411:Nerve Endings / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D013574:Synaptosomes / Q000378:metabolism
D005971:Glutamates; D018698:Glutamic Acid; D011189:Potassium Chloride; D015761:4-Aminopyridine; D010100:Oxygen; D002118:Calcium