title: Animal model of menopausal depressive-like state in female mice: prolongation of immobility time in the forced swimming test following ovariectomy.
abstract: BACKGROUND
  The onset of menopause produces a depressive state in women, but the mechanism involved in menopause-induced depression is poorly understood.
  
  
  OBJECTIVE
  Building upon previous studies that used the duration of immobility in male rodents during the forced swimming test as a behavioral measure of the depression-like state, we investigated whether the duration of immobility in female mice was altered following bilateral ovariectomy. We also evaluated the chronic effects of estradiol, antidepressants, scopolamine, and diazepam on both the duration of immobility and uterine weight.
  
  
  METHODS
  We bilaterally resected the ovaries of ICR albino female mice at 9 weeks of age. The day after the surgery, drug treatment was started once per day for 2 weeks, after which, the behavioral test was administered. The duration of immobility was measured during the last 4 min of the 6-min trial.
  
  
  RESULTS
  Bilateral ovariectomy significantly increased the duration of immobility. Chronic treatment with estradiol (15-30 microg kg(-1) day(-1)) prevented the prolongation of immobility following ovariectomy and produced a significant increase in uterine weight. Chronic treatment with imipramine, fluvoxamine, and milnacipran at 5, 10, and 15 mg kg(-1) day(-1), respectively, significantly reduced the duration of immobility, whereas treatment with scopolamine or diazepam (0.5, 1.0, and 2.0 mg kg(-1) day(-1) for both) was ineffective.
  
  
  CONCLUSIONS
  Based on these results, we suggest that the prolongation of immobility in female mice following ovariectomy may be a useful tool for investigating menopausal depression.
authors.affiliation: Behavioral Pharmacology Laboratory, Faculty of Health Sciences, Ehime University School of Medicine, Toon City, Ehime 791-0295, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Bekku
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology; D003863:Depression / Q000209:etiology*; D004195:Disease Models, Animal; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D008593:Menopause / Q000523:psychology*; D051379:Mice; D008813:Mice, Inbred ICR; D009043:Motor Activity / Q000187:drug effects; D010052:Ovariectomy; D013550:Swimming; D013997:Time Factors
chemical_list: D000928:Antidepressive Agents; D004958:Estradiol