Early weaning impairs fear extinction and decreases brain-derived neurotrophic factor expression in the prefrontal cortex of adult male C57BL/6 mice.
We examined the developmental effects of early weaning on anxiety and the extinction of fear memory in male C57BL/6 mice. Early weaning led to increased freezing behaviors after fear conditioning via the foot-shock method both during extinction training and in a test of extinction recall, but did not induce significant changes in anxiety-like behavior. In addition, we found that the levels of brain-derived neurotrophic factor (BDNF) protein and mRNA transcripts for BDNF exon III in the medial prefrontal cortex (mPFC) at the time of extinction recall were impaired in early-weaned mice compared to normally weaned mice. In light of consistent finding that early-weaned mice experience greater stress at weaning, these data suggest that early weaning of male C57BL/6 mice is valuable for studies of the pathogenesis of post-traumatic stress disorder.
Department of Animal Science and Biotechnology, Azabu University, Sagamihara, Kanagawa, Japan.
Kazutaka
K
Mogi
Department of Animal Science and Biotechnology, Azabu University, Sagamihara, Kanagawa, Japan.
Yuiko
Y
Ishida
Department of Animal Science and Biotechnology, Azabu University, Sagamihara, Kanagawa, Japan.
Miho
M
Nagasawa
Department of Animal Science and Biotechnology, Azabu University, Sagamihara, Kanagawa, Japan.
Takefumi
T
Kikusui
D000367:Age Factors; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D003214:Conditioning, Classical / Q000502:physiology*; D005108:Extinction, Psychological / Q000502:physiology*; D005239:Fear / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017397:Prefrontal Cortex / Q000378:metabolism*; D014886:Weaning
D019208:Brain-Derived Neurotrophic Factor
BDNF; PTSD; early weaning; fear extinction; mice