2004 - Neonatal dexamethasone treatment affects social behaviour of rats in later life
Patrick J. G. H. Kamphuisa, Gerda Croiseta, Joost M. Bakkerb, c, Frank van Belc, Jan M. van Reea and Victor M. Wiegant, , a
a Department of Pharmacology and Anatomy, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, PO Box 85060, 3508 AB, Utrecht, The Netherlands
b Department of Immunology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
c Department of Neonatology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The, Netherlands
Received 28 March 2002; Revised 7 April 2004; accepted 22 April 2004. Available online 15 June 2004.
Abstract
Synthetic glucocorticoids, like dexamethasone (DEX), have been frequently administered to premature infants to prevent chronic lung disease. Major concern has arisen about the long-term neurodevelopmental sequelae of this DEX treatment. In the present study, we found that neonatal DEX treatment in rats, using a treatment protocol resembling the one used in the clinical situation, increased social play behaviour in juvenile life. Furthermore, neonatal DEX treatment increased sexual motivation and intromission behaviour in the bi-level chamber, decreased submissive behaviour during an aggressive encounter, and impaired social memory in adulthood. These changes in social behaviour are not due to a general behavioural impairment since anxiety behaviour in the elevated plus maze and exploratory activity in the open-field were not affected in DEX rats. In addition, DEX rats showed no alteration in the total duration of social interest or social activity during a social interaction test. These effects of neonatal DEX treatment on behaviour later in life likely result from neurodevelopmental actions of the hormone since we found no differences in received maternal care between DEX and SAL treated pups. Together these results indicate that neonatal treatment with DEX selectively alters aspects of the behavioural response to social challenges. Thus, neonatal DEX treatment may lead to inappropriate interactions with conspecifics later in life. These data therefore warrant investigation of lasting and potentially adverse effects of treatment of human neonates with DEX on social functioning.
Author Keywords: Glucocorticoid; Play behaviour; Sexual motivation; Social defeat; Social memory; Elevated plus maze; Maternal behaviour
Corresponding author. Tel.: +31-30-2538804/8847; fax: +31-30-2539032.
Neuropharmacology
Volume 47, Issue 3 , September 2004, Pages 461-474
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