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Glial and axonal perikaryal coverage and somatic spines in the posterodorsal medial amygdala of male and cycling female rats
Author(s) -
Zancan Mariana,
Dall'Oglio Aline,
Sarzenski Taís Malysz,
Maher Martin Ian,
GarciaSegura Luis Miguel,
RasiaFilho Alberto A.
Publication year - 2015
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.23782
Subject(s) - amygdala , dendritic spine , biology , extended amygdala , glial fibrillary acidic protein , estrous cycle , somatic cell , endocrinology , neuroscience , medicine , anatomy , microbiology and biotechnology , immunohistochemistry , immunology , hippocampal formation , biochemistry , stria terminalis , gene
The posterodorsal medial amygdala (MePD) is a sex‐steroid‐sensitive area that modulates reproductive behavior in rats. The volume of the neuronal cell body, density of dendritic spines, and glial fibrillary acidic protein immunoreactivity are sexually dimorphic or affected by gonadal hormones in the MePD. Here we add new data to this panorama and describe the ultrastructure of the glial and axonal coverage of the perikaryal membrane and the somatic spines in the MePD of males and cycling females (in diestrus, early proestrus, late proestrus, and estrus). Transmission electron microscopy data (mean values from seven to 11 neurons per rat, five or six animals per group) showed that the rat MePD has most of the perikaryal membrane covered by glial processes and a relatively large amount (up to 40%) of axonal processes contacting the neuronal cell body. No statistically significant difference was found between groups for these somatic coverages ( P > 0.5). However, the density of somatic spines along the length of the perikaryal membrane was higher in the late proestrus than in estrus ( P < 0.05), and somatic spines in early and late proestrus showed variable shapes with stubby/wide, thin, mushroom‐like, ramified, transitional or atypical aspects. These findings add to the rapid adjustable synaptic changes in the MePD and in the integrated neural circuits that control neuroendocrine secretion and the hormonally modulated timely display of social behaviors in rats. J. Comp. Neurol. 523:2127–2137, 2015. © 2015 Wiley Periodicals, Inc.