Impaired imprinting and social behaviors in chicks exposed to mifepristone, a glucocorticoid receptor antagonist, during the final week of embryogenesis

Hideo Nishigori, Keisuke Kagami, Hidekazu Nishigori

Research output: Contribution to journalArticle

Abstract

The effects of glucocorticoid receptor dysfunction during embryogenesis on the imprinting abilities and social behaviors of hatchlings were examined using "fertile hen's egg-embryo-chick" system. Methods and results: Of embryos treated with mifepristone (0.4. μmol/egg) on day 14, over 75% hatched a day later than the controls (day 22) without external anomalies. The mifepristone-treated hatchlings were assayed for imprinting ability on post-hatching day 2 and for social behaviors on day 3. The findings were as follows: imprinting ability (expressed as preference score) was significantly lower in mifepristone-treated hatchlings than in controls (0.65. ± 0.06 vs. 0.92. ± 0.02, P< 0.005). Aggregation tests to evaluate the speed (seconds) required for four chicks, individually isolated with cardboard dividers in a box, to form a group after removal of the barriers showed that aggregation was significantly slower in mifepristone-treated hatchlings than in controls (8.7. ± 1.1 vs. 2.6. ± 0.3, P< 0.001). In belongingness tests to evaluate the speed (seconds) for a chick isolated at a corner to join a group of three chicks placed at the opposite corner, mifepristone-treated hatchlings took significantly longer than controls (4.5. ± 0.4/40. cm vs. 2.4. ± 0.08/40. cm, P< 0.001). In vocalization tests, using a decibel meter to measure average decibel level/30. s (chick vocalization), mifepristone-treated hatchlings had significantly weaker vocalizations than controls (14.2. ± 1.9/30. s vs. 26.4. ± 1.3/30. s P< 0.001). In conclusion, glucocorticoid receptor dysfunction during the last week embryogenesis altered the programming of brain development, resulting in impaired behavioral activities in late life.

Original languageEnglish
Pages (from-to)134-139
Number of pages6
JournalBehavioural Brain Research
Volume261
DOIs
Publication statusPublished - 2014 Mar 15

Keywords

  • Chick embryo
  • Filial imprinting
  • Glucocorticoid
  • Mifepristone
  • Prenatal exposure
  • Social behavior

ASJC Scopus subject areas

  • Behavioral Neuroscience

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