title: Post-extinction fluoxetine treatment prevents stress-induced reemergence of extinguished fear.
abstract: BACKGROUND
  The post-extinction exposure of rats to a sub-conditioning procedure (SCP; i.e., retraining with a shock intensity that is too weak to induce by itself significant fear conditioning) has been reported to provoke the reemergence of extinguished fear. This phenomenon can be prevented by chronic fluoxetine treatment.
  
  
  OBJECTIVE
  We sought to examine another potential inducer of fear reemergence, acute stress, in rats and determine whether fluoxetine prevents this phenomenon.
  
  
  METHODS
  Because in previous studies fluoxetine was administered before extinction, we first analyzed its effect on the SCP-associated reemergence of auditory-cued conditioned fear in rats injected after extinction to avoid any interaction between fluoxetine and extinction learning. Next, we used the same protocol but replaced the SCP with acute stress.
  
  
  RESULTS
  We found that the SCP and acute stress, which were carried out 3 weeks after fear extinction, similarly provoked the reemergence of extinguished fear in rats injected with vehicle during the 3-week period. In contrast, the animals treated with fluoxetine during this period behaved similarly to those not exposed to an inducer of fear reemergence.
  
  
  CONCLUSIONS
  Our data establish acute stress as an inducer of fear reemergence. The results provide further support for the hypothesis that fluoxetine interfered with mechanisms that reactivated extinguished fear, even when administered after fear extinction.
authors: Département des Sciences de la Vie, Faculté des Sciences, Université de Nice-Sophia Antipolis, 06108 Nice, France. deschaux@unice.fr
authors: Olivier
authors: O
authors: Deschaux
authors: Xigeng
authors: X
authors: Zheng
authors: Jennifer
authors: J
authors: Lavigne
authors: Ophélie
authors: O
authors: Nachon
authors: Carine
authors: C
authors: Cleren
authors: Jean-Luc
authors: JL
authors: Moreau
authors: René
authors: R
authors: Garcia
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005108:Extinction, Psychological / Q000187:drug effects; D005239:Fear / Q000187:drug effects*; D005473:Fluoxetine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*; D013315:Stress, Psychological / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D005473:Fluoxetine; D017367:Selective Serotonin Reuptake Inhibitors