ENHANCEMENT OF PEROXYNITRITE-EVOKED ACETYLCHOLINE-RELEASE BY HYDROXYLRADICAL SCAVENGERS FROM MOUSE CEREBRAL CORTICAL-NEURONS

We investigated the effects of hydroxyl radical scavengers on peroxyni trite (OONO-)-evoked acetylcholine (ACh) release from mouse cerebral c ortical neurons. N,N'-dimethylthiourea, a hydroxyl radical scavenger, dose-dependently increased OONO--evoked ACh release. Other hydroxyl ra dical scavengers such as uric acid and mannitol, also enhanced OONO--e voked 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 th e 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.