Pediatrics & Neonatology
Volume 49, Issue 2 , Pages 19-25, April 2008

Neonatal Isolation Enhances Anxiety-like Behavior Following Early-life Seizure in Rats

  • Ming-Chi Lai

      Affiliations

    • The Graduate Institute of Clinical Medical Sciences, Chang Gung University College of Medicine, Kaohsiung, Taiwan
    • Department of Pediatrics, Chi Mei Foundation Hospital, Tainan, Taiwan
    • ,
  • San-Nan Yang

      Affiliations

    • Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
    • Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
    • ,
  • Li-Tung Huang

      Affiliations

    • Department of Pediatrics, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
    • Corresponding Author InformationCorresponding author. Department of Pediatrics, Chang Gung Memorial Hospital, 123 Ta Pei Road, Niao Sung, Kaohsiung, Taiwan

Received 15 November 2007; received in revised form 2 January 2008; accepted 25 March 2008.

Article Outline

Background

Emerging evidence indicates that early adverse experiences result in the maladaptive development of the hypothalamic-pituitary-adrenal (HPA) axis and compromise the developing brain to subsequent neurological insults. Well known that mother-infant interaction plays an important role in early environment stimulation, neonatal isolation (NI) paradigm has been used as an early-life stress model in many relevant studies. Further, the effect of seizure on the developing brain is still not clarified despite more susceptibility to seizures of the developing brain. We had previously demonstrated that NI exacerbates cognitive deficit following early-life seizure. The aim of the current study was to investigate whether NI predisposes the brain to early-life seizure-induced long-term anxiety sequelae.

Methods

Rats were assigned randomly to the following four groups: (1) normal rearing rats (NR); (2) NI rats that underwent daily separation from their dams from postnatal day 2 (P2) to P9; (3) NR rats suffering lithium-pilocarpine-induced status epilepticus (SE) at P10 (NR + SE); and (4) NI + SE rats. At P60, anxiety-related behavior was evaluated using elevated plus-maze (EPM) test.

Results

SE induced in isolated rats rather than in NR rats produced a decrease in percentage of time spent in open arms, and all rats experiencing NI displayed reduced number of closed arm entries.

Conclusion

Repetitive brief NI exacerbates anxiety-related behavior in EPM test following early-life SE.

KEY WORDS:  anxiety , early-life seizures , elevated plus maze , neonatal isolation

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PII: S1875-9572(08)60006-6

doi:10.1016/S1875-9572(08)60006-6

Pediatrics & Neonatology
Volume 49, Issue 2 , Pages 19-25, April 2008

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