Removal of hydroxyl radical facilitates Ca2+-dependent [3H]GABA release by peroxynitrite.
We investigated mechanisms for enhancement of peroxynitrite (OONO-; 5 microM)-evoked [3H] gamma-aminobutyric acid (GABA) release. Hydroxyl radical scavengers such as N,N'-dimethylthiourea (DMTU), mannitol, and uric acid, significantly increased OONO--evoked [3H]GABA release, whereas urea showed no effects on the release. Removal of Ca2+ from incubation buffer abolished the enhancement of the release by DMTU, although DMTU showed no effects on the basal release with and without Ca2+ in extracellular space. These results indicate that hydroxyl radical scavengers facilitate OONO--evoked [3H]GABA release dependent on Ca2+.
Higo
A
A
Department of Pharmacology, Kawasaki Medical School, Matsushima, Kurashiki 701-0192, Japan.
Katsura
M
M
Hibino
Y
Y
Hara
A
A
Tarumi
C
C
Ohkuma
S
S
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D005333:Fetus; D016166:Free Radical Scavengers / Q000494:pharmacology; D017665:Hydroxyl Radical / Q000378:metabolism*; D008353:Mannitol / Q000494:pharmacology; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000187:drug effects; D009566:Nitrates / Q000494:pharmacology*; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology; D014316:Tritium; D014508:Urea / Q000494:pharmacology; D014527:Uric Acid / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000032:analysis / Q000378:metabolism*
D016166:Free Radical Scavengers; D009566:Nitrates; D014316:Tritium; C039642:peroxynitric acid; D014527:Uric Acid; D017665:Hydroxyl Radical; D008353:Mannitol; D005680:gamma-Aminobutyric Acid; C038983:1,3-dimethylthiourea; D014508:Urea; D013890:Thiourea; D002118:Calcium