title: Correlations between depression behaviors and sleep parameters after repeated corticosterone injections in rats.
abstract: OBJECTIVE
  Disrupted sleep may be a prodromal symptom or a predictor of depressive disorders. In this study we investigated the relationship between depression symptoms and disrupted sleep using a novel model of stress-mimicked sleep disorders in rats.
  
  
  METHODS
  SD rats were injected with corticosterone (10, 20 or 40 mg/kg, sc) or vehicle for 7 d. Their sleep-wake behavior was monitored through implanted EEG and EMG electrodes. Their depressive behaviors were assessed using forced swim test, open field test and sucrose preference test.
  
  
  RESULTS
  The corticosterone-treated rats showed significantly reduced sleep time, disinhibition of rapid-eye-movement (REM) sleep and altered power spectra during non-REM sleep. All depressive behavioral tests did not show significant difference across the groups. However, individual correlation analysis revealed statistically significance: the immobility time (despair) was negatively correlated with REM sleep latency, slow wave sleep (SWS) time ratio, SWS bouts and delta power density, and it was positively correlated with REM sleep bouts and beta power density. Meanwhile, sucrose preference (anhedonia) was positively correlated with total sleep time and light sleep bouts, and it was negatively correlated with the REM sleep time ratio.
  
  
  CONCLUSIONS
  In stress-mimicked rats, sleep disturbances are a predictor of depressive disorders, and certain symptoms of depression may be related to the disruption of several specific sleep parameters.
authors.affiliation: Dep
authors.forename: Zi-Jun
authors.initials: ZJ
authors.lastname: Wang
authors.forename: Bin
authors.initials: B
authors.lastname: Yu
authors.forename: Xue-Qiong
authors.initials: XQ
authors.lastname: Zhang
authors.forename: Zhao-Fu
authors.initials: ZF
authors.lastname: Sheng
authors.forename: Sheng-Jie
authors.initials: SJ
authors.lastname: Li
authors.forename: Yuan-Li
authors.initials: YL
authors.lastname: Huang
authors.forename: Qing
authors.initials: Q
authors.lastname: Cao
authors.forename: Xiang-Yu
authors.initials: XY
authors.lastname: Cui
authors.forename: Su-Ying
authors.initials: SY
authors.lastname: Cui
authors.forename: Yong-He
authors.initials: YH
authors.lastname: Zhang
mesh_terms: D000818:Animals; D003345:Corticosterone / Q000378:metabolism*; D003863:Depression / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep; D012893:Sleep Wake Disorders / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D013312:Stress, Physiological
chemical_list: D003345:Corticosterone