title: Highly Palatable Food during Adolescence Improves Anxiety-Like Behaviors and Hypothalamic-Pituitary-Adrenal Axis Dysfunction in Rats that Experienced Neonatal Maternal Separation.
abstract: BACKGROUND
  This study was conducted to examine the effects of ad libitum consumption of highly palatable food (HPF) during adolescence on the adverse behavioral outcome of neonatal maternal separation.
  
  
  METHODS
  Male Sprague-Dawley pups were separated from dam for 3 hours daily during the first 2 weeks of birth (maternal separation, MS) or left undisturbed (nonhandled, NH). Half of MS pups received free access to chocolate cookies in addition to ad libitum chow from postnatal day 28 (MS+HPF). Pups were subjected to behavioral tests during young adulthood. The plasma corticosterone response to stress challenge was analyzed by radioimmunoassay.
  
  
  RESULTS
  Daily caloric intake and body weight gain did not differ among the experimental groups. Ambulatory activities were decreased defecation activity and rostral grooming were increased in MS controls (fed with chow only) compared with NH rats. MS controls spent less time in open arms, and more time in closed arms during the elevated plus maze test, than NH rats. Immobility duration during the forced swim test was increased in MS controls compared with NH rats. Cookie access normalized the behavioral scores of ambulatory and defecation activities and grooming, but not the scores during the elevated plus maze and swim tests in MS rats. Stress-induced corticosterone increase was blunted in MS rats fed with chow only, and cookie access normalized it.
  
  
  CONCLUSIONS
  Prolonged access to HPF during adolescence and youth partly improves anxiety-related, but not depressive, symptoms in rats that experienced neonatal maternal separation, possibly in relation with improved function of the hypothalamic-pituitary-adrenal (HPA) axis.
authors.affiliation: Program in Craniofacial Structure and Functional Biology, Department of Dental Science, Graduate School, Seoul National University School of Dentistry, Seoul, Korea. ; Department of Oral and Maxillofacial Surgery, Seoul National University School of Dentistry, Seoul, Korea. ; Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Jong-Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Program in Craniofacial Structure and Functional Biology, Department of Dental Science, Graduate School, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Jeong Won
authors.initials: JW
authors.lastname: Jahng
keywords: Anxiety; Depression; Early life stress; Palatable food