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Original article| Volume 33, ISSUE 5, P358-366, March 01, 1993

Effects of gender and social isolation on electroencephalogram and neuroendocrine parameters in rats

  • Cindy L. Ehlers
    Correspondence
    Address reprint requests to Cindy L. Ehlers, Ph.D., The Scripps Research Institute, CVN-14, 10666 North Torrey Pines Road, La Jolla, CA 92037, USA.
    Affiliations
    Department of Neuropharmacology, The Scripps Research Institute, La Jolla, California, USA

    Department of Psychiatry, Emory University School of Medicine, Atlanta, Georgia, USA
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  • Wendy M. Kaneko
    Affiliations
    Department of Neuropharmacology, The Scripps Research Institute, La Jolla, California, USA

    Department of Psychiatry, Emory University School of Medicine, Atlanta, Georgia, USA
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  • Michael J. Owens
    Affiliations
    Department of Neuropharmacology, The Scripps Research Institute, La Jolla, California, USA

    Department of Psychiatry, Emory University School of Medicine, Atlanta, Georgia, USA
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  • Charles B. Nemeroff
    Affiliations
    Department of Neuropharmacology, The Scripps Research Institute, La Jolla, California, USA

    Department of Psychiatry, Emory University School of Medicine, Atlanta, Georgia, USA
    Search for articles by this author
DOI:https://doi.org/10.1016/0006-3223(93)90325-8
Effects of gender and social isolation on electroencephalogram and neuroendocrine parameters in rats
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      Abstract

      Social separation/isolation from either maternal or peer influence can induce a biobehavioral response in rodents and nonhuman primates seeming to mimic certain aspects of human psychopathology. To further explore this paradigm, the effects of 6 weeks of social isolation on electroencephalographic (EEG) recordings and hypothalamic-pituitary-adrenal (HPA) functioning were studied in male and female adult rats. Gender differences were observed in EEG and HPA axis functioning in these rats. Female rats, overall, were found to have higher levels of EEG slow-wave activity over the entire recording period, suggesting more intense levels of slow-wave sleep in those animals. Female rats were also observed to have overall higher plasma corticosterone concentrations and a lower anterior pituitary corticotropin-releasing factor (CRF) receptor density compared with male rats. The male rats, however, showed greater changes in response to social isolation than female rats. EEG power was increased as a result of social isolation in the male animals during the first 30–100 min of the recording. Reductions in the number of CRF receptors were also observed in the brains of the socially isolated rats in several cortical areas; however, again this effect was more prominent in the male animals. These studies suggest that gender is an important variable in determining the biobehavioral response to social isolation.

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      Article info

      Publication history

      Received in revised form: November 4, 1992
      Received: January 13, 1992

      Footnotes

      ☆These studies were partially supported by a pilot grant from the network for the psychobiology of dispression of the John D. and Catherin T. MacArthur Foundation and MIMH MH-42088. The authors thank Evie Phillips, Registered EEG Technician, for help in the statistical analysis and for records, and Susan L. Lopez, for help in the statistical analysis and for typing and editing the manuscript.

      Identification

      DOI: https://doi.org/10.1016/0006-3223(93)90325-8

      Copyright

      © 1993 Published by Elsevier Inc.

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