Sex and estrogen receptor expression influence opioid peptide levels in the mouse hippocampal mossy fiber pathway
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- 作者：Tracey A. Van Kempen ; Sana Kahlid ; Andreina D. Gonzalez ; Joanna L. Spencer-Segal ; Mumeko C. Tsuda ; Sonoko Ogawa ; Bruce S. McEwen ; Elizabeth M. Waters ; Teresa A. Milner
- 关键词：AERKO ; estrogen receptor alpha knock out mice ; BDNF ; brain derived neurotrophic factor ; BERKO ; estrogen receptor beta knock out mice ; BSA ; bovine serum albumin ; CA1 ; cornu ammonis 1 region ; CA3 ; cornu ammonis 3 region ; DG ; dentate gyrus ; DYN ; dynorphin ; E
- 刊名：Neuroscience Letters
- 出版年：2013
- 出版时间：27 September, 2013
- 年：2013
- 卷：552
- 期：Complete
- 页码：66-70
- 全文大小：1297 K
文摘
The opioid peptides, dynorphin (DYN) and enkephalin (L-ENK) are contained in the hippocampal mossy fiber pathway where they modulate synaptic plasticity. In rats, the levels of DYN and L-ENK immunoreactivity (-ir) are increased when estrogen levels are elevated (). Here, we used quantitative immunocytochemistry to examine whether opioid levels are similarly regulated in wildtype (WT) mice over the estrous cycle, and how these compared to males. Moreover, using estrogen receptor (ER) alpha and beta knock-out mice (AERKO and BERKO, respectively), the present study examined the role of ERs in rapid, membrane-initiated (6 h), or slower, nucleus-initiated (48 h) estradiol effects on mossy fiber opioid levels. Unlike rats, the levels of DYN and L-ENK-ir did not change over the estrous cycle. However, compared to males, females had higher levels of DYN-ir in CA3a and L-ENK-ir in CA3b. In WT and BERKO ovariectomized (OVX) mice, neither DYN- nor L-ENK-ir changed following 6 or 48 h estradiol benzoate (EB) administration. However, DYN-ir significantly increased 48 h after EB in the dentate gyrus (DG) and CA3b of AERKO mice only. These findings suggest that cyclic hormone levels regulate neither DYN nor L-ENK levels in the mouse mossy fiber pathway as they do in the rat. This may be due to species-specific differences in the mossy fiber pathway. However, in the mouse, DYN levels are regulated by exogenous EB in the absence of ER¦Á possibly via an ER¦Â-mediated pathway requiring new gene transcription.