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Prenatal dexamethasone augments the neurobehavioral teratology of chlorpyrifos: significance for maternal stress and preterm labor.

Publication ,  Journal Article
Levin, ED; Cauley, M; Johnson, JE; Cooper, EM; Stapleton, HM; Ferguson, PL; Seidler, FJ; Slotkin, TA
Published in: Neurotoxicol Teratol
2014

Glucocorticoids are the consensus treatment given in preterm labor and are also elevated by maternal stress; organophosphate exposures are virtually ubiquitous, so human developmental coexposures to these two agents are common. This study explores how prenatal dexamethasone exposure modifies the neurobehavioral teratology of chlorpyrifos, one of the most widely used organophosphates. We administered dexamethasone to pregnant rats on gestational days 17-19 at a standard therapeutic dose (0.2 mg/kg); offspring were then given chlorpyrifos on postnatal days 1-4, at a dose (1 mg/kg) that produces barely-detectable (<10%) inhibition of brain cholinesterase activity. Dexamethasone did not alter brain chlorpyrifos concentrations, nor did either agent alone or in combination affect brain thyroxine levels. Assessments were carried out from adolescence through adulthood encompassing T-maze alternation, Figure 8 maze (locomotor activity, habituation), novelty-suppressed feeding and novel object recognition tests. For behaviors where chlorpyrifos or dexamethasone individually had small effects, the dual exposure produced larger, significant effects that reflected additivity (locomotor activity, novelty-suppressed feeding, novel object recognition). Where the individual effects were in opposite directions or were restricted to only one agent, we found enhancement of chlorpyrifos' effects by prenatal dexamethasone (habituation). Finally, for behaviors where controls displayed a normal sex difference in performance, the combined treatment either eliminated or reversed the difference (locomotor activity, novel object recognition). Combined exposure to dexamethasone and chlorpyrifos results in a worsened neurobehavioral outcome, providing a proof-of-principle that prenatal glucocorticoids can create a subpopulation with enhanced vulnerability to environmental toxicants.

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Published In

Neurotoxicol Teratol

DOI

EISSN

1872-9738

Publication Date

2014

Volume

41

Start / End Page

35 / 42

Location

United States

Related Subject Headings

  • Toxicology
  • Stress, Psychological
  • Rats, Sprague-Dawley
  • Rats
  • Prenatal Exposure Delayed Effects
  • Premature Birth
  • Pregnancy
  • Motor Activity
  • Male
  • Insecticides
 

Citation

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Chicago
ICMJE
MLA
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Levin, E. D., Cauley, M., Johnson, J. E., Cooper, E. M., Stapleton, H. M., Ferguson, P. L., … Slotkin, T. A. (2014). Prenatal dexamethasone augments the neurobehavioral teratology of chlorpyrifos: significance for maternal stress and preterm labor. Neurotoxicol Teratol, 41, 35–42. https://doi.org/10.1016/j.ntt.2013.10.004
Levin, Edward D., Marty Cauley, Joshua E. Johnson, Ellen M. Cooper, Heather M. Stapleton, P Lee Ferguson, Frederic J. Seidler, and Theodore A. Slotkin. “Prenatal dexamethasone augments the neurobehavioral teratology of chlorpyrifos: significance for maternal stress and preterm labor.Neurotoxicol Teratol 41 (2014): 35–42. https://doi.org/10.1016/j.ntt.2013.10.004.
Levin ED, Cauley M, Johnson JE, Cooper EM, Stapleton HM, Ferguson PL, et al. Prenatal dexamethasone augments the neurobehavioral teratology of chlorpyrifos: significance for maternal stress and preterm labor. Neurotoxicol Teratol. 2014;41:35–42.
Levin, Edward D., et al. “Prenatal dexamethasone augments the neurobehavioral teratology of chlorpyrifos: significance for maternal stress and preterm labor.Neurotoxicol Teratol, vol. 41, 2014, pp. 35–42. Pubmed, doi:10.1016/j.ntt.2013.10.004.
Levin ED, Cauley M, Johnson JE, Cooper EM, Stapleton HM, Ferguson PL, Seidler FJ, Slotkin TA. Prenatal dexamethasone augments the neurobehavioral teratology of chlorpyrifos: significance for maternal stress and preterm labor. Neurotoxicol Teratol. 2014;41:35–42.
Journal cover image

Published In

Neurotoxicol Teratol

DOI

EISSN

1872-9738

Publication Date

2014

Volume

41

Start / End Page

35 / 42

Location

United States

Related Subject Headings

  • Toxicology
  • Stress, Psychological
  • Rats, Sprague-Dawley
  • Rats
  • Prenatal Exposure Delayed Effects
  • Premature Birth
  • Pregnancy
  • Motor Activity
  • Male
  • Insecticides