β-endorphin cells in the arcuate nucleus:: Projections to the supraoptic nucleus and changes in expression during pregnancy and parturition
β-endorphin cells in the arcuate nucleus:: Projections to the supraoptic nucleus and changes in expression during pregnancy and parturition
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DOI：
10.1046/j.1365-2826.2002.00837.x
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发表时间：
2002-10-01
影响因子：
3.2
通讯作者：
Meddle, SL
中科院分区：
文献类型：
--
作者：
Douglas, AJ;Bicknell, RJ;Meddle, SL
视上核催产素神经元的活性和分泌在妊娠晚期和分娩时被内源性阿片类药物抑制。在这里，我们研究了怀孕大鼠弓状核中β-内啡肽/阿片黑皮质素原神经元的投射和基因表达的变化。发现弓状核的所有区域都含有对从视上核逆行转运的β-内啡肽荧光微珠和双标记神经元（β-内啡肽加微珠）产生免疫反应的细胞，表明整个弓状核的β-内啡肽神经元投射到视上核。妊娠晚期和分娩时，弓状核中β-内啡肽免疫反应细胞数量增加，视上核和视上周围区域β-内啡肽纤维密度增加，表明β-内啡肽表达增强，视上核β-内啡肽神经支配增加。与妊娠早期相比，妊娠晚期弓状核中阿片黑皮质素原 mRNA 表达增加：尾部区域阳性神经元的数量显着增加。在发情前期和临产大鼠中，弓状核中的 Fos 表达（神经元激活指标）共定位于 β-内啡肽神经元，但阳性细胞数量在分娩过程中并未增加，表明出生时缺乏 β-内啡肽神经元激活。因此，弓状核中的β-内啡肽细胞投射到视上核，并且怀孕期间神经支配的增加可以解释催产素神经元的内源性阿片类药物抑制增强。
Supraoptic nucleus oxytocin neurone activity and secretion are inhibited in late pregnancy and parturition by endogenous opioids. Here, we investigated alterations in the projections and gene expression of beta-endorphin/pro-opiomelanocortin neurones in the arcuate nucleus in the pregnant rat. All regions of the arcuate nucleus were found to contain cells immunoreactive for beta-endorphin fluorescent microbeads retrogradely transported from the supraoptic nucleus, and double-labelled neurones (beta-endorphin plus microbeads), showing that beta-endorphin neurones throughout the arcuate nucleus project to the supraoptic nucleus. There was an increase in the number of beta-endorphin-immunoreactive cells in the arcuate nucleus and an increase in the density of beta-endorphin fibres within the supraoptic nucleus and peri-supraoptic region in late pregnancy and parturition, suggesting enhanced expression of beta-endorphin and increased beta-endorphin innervation of the supraoptic nucleus. Pro-opiomelanocortin mRNA expression in the arcuate nucleus increased in late compared to early pregnancy: the number of positive neurones significantly increased in the caudal region. Fos expression (an indicator of neuronal activation) in the arcuate nucleus was colocalized in beta-endorphin neurones in both proestrus and parturient rats, but the number of positive cells did not increase during parturition, suggesting lack of activation of beta-endorphin neurones at birth. Thus, beta-endorphin cells in the arcuate nucleus project to the supraoptic nucleus and increased innervation during pregnancy may explain the enhanced endogenous opioid inhibition of oxytocin neurones.