Peroxide effects on [3H]L-glutamate release by synaptosomes isolated from the cerebral cortex.
Basal (non-depolarized) and high K(+)-stimulated [3H]L-glutamate release in the presence and absence of Ca2+ were assessed using presynaptic nerve terminals (synaptosomes) isolated from the cerebral cortex of the guinea pig. Basal glutamate release was found to be Ca(2+)-independent and was significantly increased following treatment with hydrogen peroxide (H2O2). On the other hand, depolarization-induced release had both a Ca(2+)-dependent and Ca(2+)-independent component. Both components of stimulated release were suppressed by H2O2. In fact, Ca(2+)-dependent evoked release was virtually eliminated by H2O2 pretreatment. The data suggest that H2O2 exerts a differential effect on the neurochemical mechanisms involved in basal and stimulated glutamate release at the presynaptic nerve terminal.
Physiology Department, Armed Forces Radiobiology Research Institute, Bethesda, MD 20889-5145.
S C
SC
Gilman
M J
MJ
Bonner
T C
TC
Pellmar
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002540:Cerebral Cortex / Q000648:ultrastructure; D005609:Free Radicals; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D006168:Guinea Pigs; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008297:Male; D013574:Synaptosomes / Q000187:drug effects* / Q000378:metabolism
D005609:Free Radicals; D005971:Glutamates; D018698:Glutamic Acid; D006861:Hydrogen Peroxide; D002118:Calcium