Ontogenetic alterations in molecular and structural correlates of dendritic growth after developmental exposure to polychlorinated biphenyls

Pamela J Lein, Dongren Yang, Adam D. Bachstetter, Hugh A. Tilson, G. Jean Harry, Ronald F. Mervis, Prasada Rao S Kodavanti

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

Objective: Perinatal exposure to polychlorinated biphenyls (PCBs) is associated with decreased IQ scores, impaired learning and memory, psychomotor difficulties, and attentional deficits in children. It is postulated that these neuropsychological deficits reflect altered patterns of neuronal connectivity. To test this hypothesis, we examined the effects of developmental PCB exposure on dendritic growth. Methods: Rat dams were gavaged from gestational day 6 through postnatal day (PND) 21 with vehicle (corn oil) or the commercial PCB mixture Aroclor 1254 (6 mg/kg/day). Dendritic growth and molecular markers were examined in pups during development. Results: Golgi analyses of CA1 hippocampal pyramidal neurons and cerebellar Purkinge cells indicated that developmental exposure to PCBs caused a pronounced age-related increase in dendritic growth. Thus, even though dendritic lengths were significantly attenuated in PCB-treated animals at PND22, the rate of growth was accelerated at later ages such that by PND60, dendritic growth was comparable to or even exceeded that observed in vehicle controls. Quantitative reverse transcriptase polymerase chain reaction analyses demonstrated that from PND4 through PND21, PCBs generally increased expression of both spinophilin and RC3/neurogranin mRNA in the hippocampus, cerebellum, and cortex with the most significant increases observed in the cortex. Conclusions: This study demonstrates that developmental PCB exposure alters the ontogenetic profile of dendritogenesis in critical brain regions, supporting the hypothesis that disruption of neuronal connectivity contributes to neuropsychological deficits seen in exposed children.

Original languageEnglish (US)
Pages (from-to)556-563
Number of pages8
JournalEnvironmental Health Perspectives
Volume115
Issue number4
DOIs
StatePublished - Apr 2007
Externally publishedYes

Keywords

  • Dendritogenesis
  • Developmental neurotoxicology
  • Learning and memory
  • Molecular markers
  • Polychlorinated biphenyls

ASJC Scopus subject areas

  • Environmental Science(all)
  • Environmental Chemistry
  • Public Health, Environmental and Occupational Health

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