Re-evaluation of connexins associated with motoneurons in rodent spinal cord, sexually dimorphic motor nuclei and trigeminal motor nucleus
Re-evaluation of connexins associated with motoneurons in rodent spinal cord, sexually dimorphic motor nuclei and trigeminal motor nucleus
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DOI：
10.1111/ejn.12450
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发表时间：
2014-03-01
影响因子：
3.4
通讯作者：
Nagy, J. I.
中科院分区：
文献类型：
--
作者：
Bautista, W.;Rash, J. E.;Nagy, J. I.
由连接蛋白36（connexin 36，Cx 36）组成的神经元间隙连接形成的电突触是哺乳动物脑回路中的常见特征，但对它们在脊髓中的分布知之甚少。已有报道基于连接蛋白mRNA和/或蛋白检测，发育和/或成熟的运动神经元表达多种连接蛋白，包括三叉神经运动神经元中的Cx 26、Cx 32、Cx 36和Cx43，脊髓运动神经元中的Cx 36、Cx 37、Cx40、Cx43和Cx45，以及性二态运动神经元中的Cx 32。我们重新研究了这些连接蛋白在出生后的发展，并在成年大鼠和小鼠使用免疫荧光标记的每个连接蛋白的本地化。我们发现Cx 26只与三叉神经运动核（Mo 5）中的软脑膜相关，Cx 32只与该核和脊髓中运动神经元之间的少突胶质细胞和有髓纤维相关，Cx 37，Cx40和Cx45只与脊髓腹角中的血管相关，包括运动神经元之间的血管。通过冷冻断裂复制免疫标记，基于Cx43的免疫金标记，发现>100个星形胶质细胞间隙连接，但没有神经元间隙连接，而基于Cx 36标记，在出生后（P）4、P7和P18检测到16个神经元间隙连接。Cx 36的点状标记定位于外周蛋白阳性运动神经元的Mo 5，整个脊髓的运动神经元，和性二态运动神经元在较低的腰椎水平的躯体和树突状表面。在电突触和电传输之间的发展和成人运动神经元的研究中，我们的研究结果有助于集中注意力调解这种传输的缝隙连接组成的Cx 36。
Electrical synapses formed by neuronal gap junctions composed of connexin36 (Cx36) are a common feature in mammalian brain circuitry, but less is known about their deployment in spinal cord. It has been reported based on connexin mRNA and/or protein detection that developing and/or mature motoneurons express a variety of connexins, including Cx26, Cx32, Cx36 and Cx43 in trigeminal motoneurons, Cx36, Cx37, Cx40, Cx43 and Cx45 in spinal motoneurons, and Cx32 in sexually dimorphic motoneurons. We re-examined the localization of these connexins during postnatal development and in adult rat and mouse using immunofluorescence labeling for each connexin. We found Cx26 in association only with leptomeninges in the trigeminal motor nucleus (Mo5), Cx32 only with oligodendrocytes and myelinated fibers among motoneurons in this nucleus and in the spinal cord, and Cx37, Cx40 and Cx45 only with blood vessels in the ventral horn of spinal cord, including those among motoneurons. By freeze-fracture replica immunolabeling, >100 astrocyte gap junctions but no neuronal gap junctions were found based on immunogold labeling for Cx43, whereas 16 neuronal gap junctions at postnatal day (P)4, P7 and P18 were detected based on Cx36 labeling. Punctate labeling for Cx36 was localized to the somatic and dendritic surfaces of peripherin-positive motoneurons in the Mo5, motoneurons throughout the spinal cord, and sexually dimorphic motoneurons at lower lumbar levels. In studies of electrical synapses and electrical transmission between developing and between adult motoneurons, our results serve to focus attention on mediation of this transmission by gap junctions composed of Cx36.