Infusion of flesinoxan into the amygdala blocks the fear-potentiated startle.
In a previous study it was demonstrated that flesinoxan, a selective serotonin (5-HT)1A receptor agonist, had anxiolytic properties in the fear-potentiated startle paradigm. The present study investigated the putative site of action of flesinoxan in this paradigm. Flesinoxan infused either into the dorsal raphe nucleus or the median raphe nucleus did not affect startle potentiation. Bilateral infusion of flesinoxan into the central nucleus of the amygdala on the other hand, dose-dependently blocked the fear-potentiated startle response. These data indicate that flesinoxan exerts it anxiolytic effects in the fear-potentiated startle paradigm via the central nucleus of the amygdala, whereas the dorsal and median raphe nuclei are not directly involved in this process.
Department of Psychopharmacology, Faculty of Pharmacy, Utrecht University, The Netherlands.
L
L
Groenink
R J
RJ
Joordens
T H
TH
Hijzen
A
A
Dirks
B
B
Olivier
D000679:Amygdala / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D014151:Anti-Anxiety Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005239:Fear; D007839:Functional Laterality; D007263:Infusions, Parenteral; D008297:Male; D010879:Piperazines / Q000008:administration & dosage / Q000494:pharmacology*; D011903:Raphe Nuclei / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000502:physiology; D044263:Receptors, Serotonin, 5-HT1; D013216:Reflex, Startle / Q000187:drug effects* / Q000502:physiology
D014151:Anti-Anxiety Agents; D010879:Piperazines; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; C056895:flesinoxan