Enhancement of peroxynitrite-evoked acetylcholine release by hydroxyl radical scavengers from mouse cerebral cortical neurons

We investigated the effects of hydroxyl radical scavengers on peroxynitrite (OONO-)-evoked acetylcholine (ACh) release from mouse cerebral cortical neurons. N,N'-dimethylthiourea, a hydroxyl radical scavenger, dose-dependently increased OONO--evoked ACh release. Other hydroxyl radical scavengers such as uric acid and mannitol, also enhanced OONO--evoked ACh release; although these enhancing effects were not found in the absence of OONO-. In addition, OONO--induced [Ca-45(2+)]influx was significantly facilitated by the scavengers, whereas no effects of the scavengers on [Ca-45(2+)]influx was observed in the absence of OONO-. These results indicate that hydroxyl radical scavengers enhance OONO--evoked ACh release via the facilitation of OONO--induced [Ca-45(2+)]influx.