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REPEATED MATERNAL SEPARATION IN THE NEONATAL RAT: CELLULAR MECHANISMS CONTRIBUTING TO BRAIN GROWTH SPARING
Lau, C., A. Cameron, AND L. Antolick. REPEATED MATERNAL SEPARATION IN THE NEONATAL RAT: CELLULAR MECHANISMS CONTRIBUTING TO BRAIN GROWTH SPARING. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/125 (NTIS PB93181139).
Separation of rat neonates from their dam has been shown to evoke acutely a variety of biochemical and physiological responses. n the current study, we examined whether these responses were extended to pups who were subject to daily episodes of maternal deprivation, and whether this repeated stress paradigm was associated with corresponding changes of cellular growth and maturation. ups were removed from their, nursing dams for 6 h daily beginning at 4 days of age until weaning at 21 days. n another group, pups were deprived for only a single episode and examined immediately for the acute study. lasma corticosterone levels of the deprived pups were elevated significantly at the end of a single or each repeated stress episode. he repeating stress paradigm did not influence the magnitude of this hormonal response at the ensuing ages. onsistent with previous findings, ornithine decarboxylase (ODC) activities in liver, kidney, heart and lung were markedly depressed in pups subject to a single episode of maternal separation stress. rain ODC activities were@not affected by the separation stress at early ages, but by day 8 and thereafter, the enzyme activities were also suppressed. n the repeated deprivation study, ODC activities in the peripheral tissues were consistently depressed after each episode of stress, but appeared to recover to 4 control values 18 h after each insult.
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Record Details:Record Type: DOCUMENT (REPORT)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY