Infusion of flesinoxan into the amygdala blocks the fear-potentiated startle

In a previous study it was demonstrated that flesinoxan, a selective seroto nin (5-HT)(1A) receptor agonist, had anxiolytic properties in the fear-pote ntiated startle paradigm. The present study investigated the putative site of action of flesinoxan in this paradigm. Flesinoxan infused either into th e dorsal raphe nucleus or the median raphe nucleus did not affect startle p otentiation. Bilateral infusion of flesinoxan into the central nucleus of t he amygdala on the other hand, dose-dependently blocked the fear-potentiate d startle response. These data indicate that flesinoxan exerts it anxiolyti c effects in the fear-potentiated startle paradigm via the central nucleus of the amygdala, whereas the dorsal and median raphe nuclei are not directl y involved in this process. NeuroReport 11:2285-2288 (C) 2000 Lippincon Wil liams & Wilkins.