Neural Regeneration Research ›› 2013, Vol. 8 ›› Issue (2): 149-155.doi: 10.3969/j.issn.1673-5374.2013.02.007

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Sex differences in estrogen receptor promoter expression in the area postrema

Chunxiao Zhang1, Tomohiro Hamada2   

  1. 1 Department of Physiology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, Jilin Province, China
    2 Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
  • Received:2012-06-01 Revised:2012-11-05 Online:2013-01-15 Published:2013-01-15
  • Contact: Tomohiro Hamada, Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan,hamada@nms.ac.jp.
  • About author:Chunxiao Zhang☆, Ph.D., Associate professor.
  • Supported by:

    This study was supported by a Japan-China Sasakawa Medical Fellowship from the Japan China Medical Association.

Abstract:

Estrogen receptor α is widely distributed in the rat brain, but the tissue- or target-specificity of the estrogen receptor α gene promoters remains unknown. In the present study, we used transgenic rats expressing enhanced green fluorescent protein under the control of the estrogen receptor α 0/B promoter to examine expression driven by this promoter in two significant nuclei that regulate cardiovascular activity, the area postrema and the nucleus tractus solitarius. Immunohistochemistry showed that enhanced green fluorescent protein-labeled cells were distributed in the area postrema and the nucleus tractus solitarius of both female and male transgenic rats, and a neural network of enhanced green fluorescent protein-positive fibers was seen between the area postrema and the nucleus tractus solitarius. The number of enhanced green fluorescent protein-labeled cells in the area postrema of female rats was significantly higher than in the males, but no significant difference was found in the number of enhanced green fluorescent protein-labeled cells in the nucleus tractus solitarius. The sex differences in the number of enhanced green fluorescent protein-labeled cells in the area postrema was not affected after ovariectomy or 17β-estradiol benzoate treatment in adult rats. Our results suggest that the effects of estrogen in the area postrema are related to the expression of estrogen receptor α under the control of the 0/B promoter, and changes in the sex hormone environment in the adult period do not affect estrogen receptor α expression in the area postrema or the nucleus tractus solitarius.

Key words: neural regeneration, basic research, estrogen receptor &alpha, promoter, green fluorescent protein, sex differences, area postrema, nucleus tractus solitarius, medulla, estrogen, rats, grant-supported paper, photographs-containing paper, neuroregeneration