NEUROTRANSMITTER PHENOTYPES OF DESCENDING SYSTEMS IN THE RAT LUMBAR SPINAL CORD
NEUROTRANSMITTER PHENOTYPES OF DESCENDING SYSTEMS IN THE RAT LUMBAR SPINAL CORD
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DOI：
10.1016/j.neuroscience.2012.09.037
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发表时间：
2012-12-27
期刊：
影响因子：
3.3
通讯作者：
Maxwell, D. J.
中科院分区：
文献类型：
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作者：
Du Beau, A.;Shrestha, S. Shakya;Maxwell, D. J.
大脑的下行系统对脊髓内的感觉和运动过程产生重大影响。尽管已知许多下行系统对脊髓神经元具有兴奋作用，但我们对它们使用的递质表型的了解仍然存在空白。在这项研究中，我们研究了皮质脊髓束（CST）中轴突的递质表型；红核脊髓束（RST）；前庭脊髓束的外侧部分（VST）；和网状脊髓束（ReST）。通过将霍乱毒素（CTb）b亚基立体定向注射到运动皮层、红核、外侧前庭核和内侧纵束（MLF）中，分别标记CST、RST、VST和ReST轴突，顺行标记它们。使用免疫荧光技术研究了腰段中标记轴突的神经递质含量；针对囊泡谷氨酸转运蛋白（VGLUT1 和 VGLUT2）的抗体用于识别谷氨酸能末端，囊泡 GABA 转运蛋白（VGAT）用于识别 GABA 和甘氨酸末端。结果显示，几乎所有 CST（96%）轴突都含有 VGLUT1，而几乎所有 RST（97%）和 VST（97%）轴突都含有 VGLUT1。 轴突含有 VGLUT2。尽管大多数 ReST 轴突包含 VGLUT2 (59%)，但相当少数包含 VGAT (20%)，并且这些终端中的大多数可以细分为 GABA 能或甘氨酸能，因为仅发现这两种递质共定位的证据有限。此外，有一群 REST 终端显然不包含所测试递质的标记，并且不具有血清素能。我们可以得出结论，CST、RST 和 VST 是“纯”兴奋性系统，而 ReST 由兴奋性和抑制性轴突的异质群体组成。预计该信息将使脊柱网络的输入能够更有信心地定义。 (C) 2012 年国际广播组织。由爱思唯尔有限公司出版。保留所有权利。
Descending systems from the brain exert a major influence over sensory and motor processes within the spinal cord. Although it is known that many descending systems have an excitatory effect on spinal neurons, there are still gaps in our knowledge regarding the transmitter phenotypes used by them.In this study we investigated transmitter phenotypes of axons in the corticospinal tract (CST); the rubrospinal tract (RST); the lateral component of the vestibulospinal tract (VST); and the reticulospinal tract (ReST). They were labelled anterogradely by stereotaxic injection of the b subunit of cholera toxin (CTb) into the motor cortex, red nucleus, lateral vestibular nucleus and medial longitudinal fascicle (MLF) to label CST, RST, VST and ReST axons respectively. Neurotransmitter content of labelled axons was investigated in lumbar segments by using immunoflurescence; antibodies against vesicular glutamate transporters (VGLUT1 and VGLUT2) were used to identify glutamatergic terminals and the vesicular GABA transporter (VGAT) was used to identify GABA- and glycinergic terminals.The results show that almost all CST (96%) axons contain VGLUT1 whereas almost all RST (97%) and VST (97%) axons contain VGLUT2. Although the majority of ReST axons contain VGLUT2 (59%), a sizable minority contains VGAT (20%) and most of these terminals can be subdivided into those that are GABAergic or those that are glycinergic because only limited evidence for co-localisation was found for the two transmitters. In addition, there is a population of REST terminals that apparently does not contain markers for the transmitters tested and is not serotoninergic.We can conclude that the CST, RST and VST are 'pure' excitatory systems whereas the ReST consists of a heterogeneous population of excitatory and inhibitory axons. It is anticipated that this information will enable inputs to spinal networks to be defined with greater confidence. (C) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.