Effects of neonatal dexamethasone treatment on hippocampal synaptic function

Hsiao Ju Lin, Chiung Chun Huang, Kuei Sen Hsu

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

Objective: Synthetic glucocorticoid dexamethasone (DEX) is frequently used as a therapeutic agent to lessen the morbidity of chronic lung disease in premature infants. Surprisingly, little is known about the long-term neurodevelopmental outcomes of this therapy. Methods: Using a schedule of tapering doses of DEX similar to that used in premature infants, we examined the consequences of neonatal DEX treatment on hippocampal synaptic plasticity of infants and associative memory later in their lives. Results: Neonatal DEX treatment changed the direction of synaptic plasticity, favoring low-frequency, stimulation-induced, long-term depression and opposing the induction of long-term potentiation by high-frequency stimulation in adolescent (5-week-old) rats, but these alterations disappeared in young adult (8-week-old) rats. The effects of DEX on long-term depression and long-term potentiation were found to correlate with an increase in the autophosphorylation of Ca2+/ calmodulin-dependent protein kinase II and a decrease in the protein phosphatase 1 activity. Neonatal DEX treatment also disrupted memory retention in 5-week-old (but not 8-week-old) rats subjected to passive avoidance learning tasks. Interpretation: These results suggest that neonatal DEX treatment alters hippocampal synaptic plasticity and contextual fear memory formation in later life, but these impairments apparently are not permanent.

Original languageEnglish
Pages (from-to)939-951
Number of pages13
JournalAnnals of Neurology
Volume59
Issue number6
DOIs
Publication statusPublished - 2006 Jun

All Science Journal Classification (ASJC) codes

  • Neurology
  • Clinical Neurology

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