Expression of GalR1 and GalR2 galanin receptor messenger ribonucleic acid in proopiomelanocortin neurons of the rat arcuate nucleus: Effect of testosterone
Expression of GalR1 and GalR2 galanin receptor messenger ribonucleic acid in proopiomelanocortin neurons of the rat arcuate nucleus: Effect of testosterone
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DOI：
10.1210/en.141.5.1780
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发表时间：
2000-05-01
期刊：
影响因子：
4.8
通讯作者：
Mitchell, V
中科院分区：
文献类型：
--
作者：
Bouret, S;Prevot, V;Mitchell, V
以往的研究表明，含有甘丙肽的纤维与弓状核的POMC神经元形成突触联系。然而，POMC神经元表达甘丙肽受体的能力从未被评估过。本研究旨在探讨POMC神经元是否表达甘丙肽受体信使RNA（mRNA），以及睾酮是否可以调节甘丙肽受体基因的表达。双标记原位杂交组织化学，使用S-35标记（甘丙肽受体GalR 1或GalR 2）和地高辛标记（POMC）的核糖核酸探针，从完整的，去势，和睾丸激素替代的成年雄性大鼠的脑切片进行。为了分析，弓状核被分为四个喙尾区。结果表明，GalR 1和GalR 2 mRNA在POMC神经元中均有表达。大多数表达甘丙肽受体mRNA的POMC神经元被发现在核的吻侧部分。去势降低了甘丙肽受体mRNA在POMC神经元的标记密度，和睾酮阻止去势的影响，在所有的吻尾细分的弓状核。总而言之，这些数据表明甘丙肽可以通过对GalR 1或GalR 2受体的作用直接调节POMC神经元的活性，特别是在吻弓状核中。此外，睾酮可以调节GalR 1和GalR 2的表达。由于POMC神经元位于核的吻侧部分是已知的项目优先视前区，表达甘丙肽受体基因的POMC神经元可能在调节GnRH神经内分泌轴中发挥重要作用。
Previous studies have shown that galanin-containing fibers make synaptic contacts with POMC neurons in the arcuate nucleus. However, the ability of POMC neurons to express galanin receptors has never been assessed. The present study was designed to investigate whether POMC neurons express galanin receptor messenger RNA (mRNA) and whether testosterone could modulate galanin receptor gene expression. A dual-labeling in situ hybridization histochemistry, using S-35-labeled (galanin receptors GalR1 or GalR2) and digoxigenin-labeled (POMC) riboprobes, was performed on brain sections from intact, castrated, and testosterone-replaced adult male rats. For analysis, the arcuate nucleus was divided into four rostro-caudal areas. The results revealed that both GalR1 and GalR2 mRNAs were expressed in POMC neurons. Most POMC neurons expressing galanin receptor mRNAs were found in the rostral parts of the nucleus. Castration reduced the labeling density of galanin receptor mRNAs in POMC neurons, and testosterone prevented the effects of castration in all rostro-caudal subdivisions of the arcuate nucleus. Taken together, these data indicate that galanin can directly modulate the activity of POMC neurons, via an action on GalR1 or GalR2 receptors, particularly in the rostral-arcuate nucleus. In addition, testosterone can modulate the expression of GalR1 and GalR2. Because POMC neurons located in the rostral part of the nucleus are known to project preferentially to the preoptic area, POMC neurons expressing the galanin receptor genes may play an important role in the regulation of the GnRH neuroendocrine axis.