Three-dimensional properties of GnRH neuroterminals in the median eminence of young and old rats.
Three-dimensional properties of GnRH neuroterminals in the median eminence of young and old rats.
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DOI：
10.1002/cne.22156
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发表时间：
2009-11-20
期刊：
影响因子：
--
通讯作者：
Gore AC
中科院分区：
文献类型：
--
作者：
Yin W;Mendenhall JM;Monita M;Gore AC
The decapeptide GnRH that regulates reproduction in all vertebrates is stored in, and secreted from, large dense-core secretory vesicles in nerve terminals in the median eminence. GnRH is released from these terminals with biological rhythms that are critical for the maintenance of normal reproduction. During reproductive aging in female rats, there is a loss of GnRH pulses and a diminution of the GnRH surge. However, information about the specific role of GnRH nerve terminals is lacking, particularly in the context of aging. We sought to gain novel ultrastructural information about GnRH neuroterminals by performing three-dimensional (3D) reconstructions of GnRH neuroterminals and their surrounding microenvironment in the median eminence of young (4-5 month) and old (22-24 month) ovariectomized Sprague-Dawley female rats. Median eminence tissues were freeze-plunge embedded, and serial ultrathin sections were collected on slot grids for immunogold labeling of GnRH immunoreactivity. Sequential images were used to create 3D models of GnRH terminals. These reconstructions provided novel perspectives into the morphological properties of GnRH terminals, and their neural and glial environment. We also noted that the cytoarchitectural features of the median eminence became disorganized with aging. Quantitative measures showed a significant decrease in the apposition between GnRH terminal membranes and glial cells. Our data suggest reproductive aging in rats is characterized by structural organizational changes to the GnRH terminal microenvironment in the median eminence.
