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Estrogen alters mean numbers of NeuN‐labeled neurons in the medial amygdala (MeA) of ovariectomized (OVX) rats in a dose‐ and time‐dependent manner
Author(s) -
Fan Lu,
Hanbury Rose,
Pandey Subhash C.,
Cohen Rochelle S
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a597
Subject(s) - neun , amygdala , endocrinology , ovariectomized rat , medicine , immunoperoxidase , neuron , chemistry , estrogen , biology , neuroscience , antibody , immunohistochemistry , immunology , monoclonal antibody
We demonstrated that supraphysiological and some physiological regimens of 17â‐estradiol benzoate (E2) alter mean numbers of cell nuclei immunolabeled for phosphorylated cyclic AMP response element‐binding protein (pCREB) in the MeA, a brain region involved in emotional processing, in OVX rats. Immunolabeling in the MeA may be due to increased pCREB expression in individual nuclei or increased numbers of neurons. We, therefore, addressed the hypothesis that E2 alters the mean number of neurons labeled with antibodies to neuron–specific protein (NeuN) using immunoperoxidase techniques. Sprague Dawley OVX rats (N=4 per group) were injected (s. c.) with one of the following E2 regimes: 2.5μg for 4 (2.5/4) or 14 (2.5/14) days or 10μg E2 for 14 days (10/14); sesame oil (SO) was the control. Both 2.5μg E2 treatments resulted in physiological blood E2 levels, but the 10/14 regimen resulted in levels that were 2.5X higher. Using StereoInvestigator (MicroBrightField) software, we found a significant increase in the mean number of NeuN‐labeled neurons in the left and right hemispheres of the MeA in the 10/14 and 2.5/14 groups compared to the 2.5/4 and SO groups. No differences in this parameter were seen in either hemisphere of the central amygdala. Our results suggest that E2 has the ability to increase the number neurons in specific structures of amygdala. Supported by NIH grant MH065990.