title: Behaviour of a genetic mouse model of depression in the learned helplessness paradigm.
abstract: BACKGROUND
  H/Rouen (displaying a helpless phenotype in the tail suspension test) mice exhibiting features of depressive disorders and NH/Rouen (displaying non-helpless phenotype) mice were previously created through behavioural screening and selective breeding. Learned helplessness (LH), in which footshock stress induces a coping deficit, models some aspects of depression in rodents, but so far, fewer LH studies have been performed in mice than in rats.
  
  
  OBJECTIVE
  To study H/Rouen and NH/Rouen in the LH paradigm.
  
  
  RESULTS
  When CD1 mice were submitted to footshock with various training durations and shock intensities, the most suitable parameters to induce a behavioural deficit were 0.3 mA and four training sessions. A significantly longer latency to escape shocks was found in male H/Rouen mice compared to male NH/Rouen mice. On the other hand, once shocked, NH/Rouen mice showed more severe coping deficits than H/Rouen mice. In addition, a sub-chronic treatment with fluoxetine lacked efficacy in NH/Rouen mice, whereas it improved performances in H/Rouen mice. We also found that a shock reminder at day 8, subsequent to inescapable shocks, maintained helplessness for 20 days. Finally, female H/Rouen mice responded to chronic fluoxetine administration after 10 days of treatment, while a 20-day treatment was necessary to improve the behavioural deficit in H/Rouen male mice.
  
  
  CONCLUSIONS
  H/Rouen and NH/Rouen lines displayed different despair-related behaviour in the LH paradigm. Fluoxetine had beneficial effects after sub-chronic or chronic but not acute treatment of H/Rouen mice, thus providing a pharmacological validation of the protocols.
authors.affiliation: Centre de Recherche en Neurosciences de Lyon, CNRS UMR 5292/INSERM U1028 Physiopathologie des réseaux neuronaux du cycle veille-sommeil, Faculté de Pharmacie, Université Lyon 1, Lyon, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Bougarel
authors.forename: Jérôme
authors.initials: J
authors.lastname: Guitton
authors.forename: Luc
authors.initials: L
authors.lastname: Zimmer
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Vaugeois
authors.forename: Malika
authors.initials: M
authors.lastname: El Yacoubi
mesh_terms: D000818:Animals; D018687:Antidepressive Agents, Second-Generation / Q000008:administration & dosage / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects; D003863:Depression / Q000188:drug therapy / Q000235:genetics / Q000503:physiopathology*; D004195:Disease Models, Animal; D004334:Drug Administration Schedule; D005260:Female; D005473:Fluoxetine / Q000008:administration & dosage / Q000494:pharmacology*; D006380:Helplessness, Learned; D008297:Male; D051379:Mice; D012737:Sex Factors; D013997:Time Factors
chemical_list: D018687:Antidepressive Agents, Second-Generation; D005473:Fluoxetine