Direct evidence of an extensive GABAergic innervation of the spinal dorsal horn by fibres descending from the rostral ventromedial medulla
Direct evidence of an extensive GABAergic innervation of the spinal dorsal horn by fibres descending from the rostral ventromedial medulla
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DOI：
10.1016/0306-4522(96)00063-2
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发表时间：
1996-07-01
期刊：
影响因子：
3.3
通讯作者：
StormMathisen, J
中科院分区：
文献类型：
--
作者：
Antal, M;Petko, M;StormMathisen, J
许多研究强调了延髓头端腹内侧区的多巴胺能神经纤维在脊髓伤害性信息处理中的作用。然而，越来越多的证据表明，5-羟色胺从延髓头端腹内侧对脊髓神经元活动的介导的相对贡献可能需要重新评估。最近证实，除了肾上腺素能纤维，脊髓背角还接受来自延髓头端腹内侧的大量非肾上腺素能投射。此外，在延髓头端腹内侧的刺激可能会导致一个强大的抑制伤害性脊髓丘脑束细胞没有任何可检测到的血清素释放的背角。用顺行性轴突示踪剂菜豆白细胞凝集素（Phaseolusvulgaris leucoagglutinin）在大鼠延髓头端腹内侧中央区电离子透入标记中缝-脊髓轴突和轴突终末（中缝大核）的突触后标记，并通过植入后免疫细胞化学方法揭示标记中缝-脊髓终末及其突触后靶点的GABA和甘氨酸免疫反应，在这里，我们证明了广泛的γ-氨基丁酸能投射从头端腹内侧延髓到脊髓背角。我们发现，大多数标记中缝脊神经末梢在板层I-IIo和IV-V含有GABA和一些GABA免疫反应的终端也免疫反应甘氨酸。我们还发现，GABA免疫反应中缝-脊髓终末主要与GABA和甘氨酸阴性的，可能是兴奋性的脊髓神经元，包括钙结合蛋白-D-28 k-以及小清蛋白免疫反应细胞在I-IIo和IV-V层建立突触联系。在某些情况下，可能与甘氨酸一起作用，可能在抑制脊髓背角的伤害性信息处理中起关键作用，但大多数尚未确定。版权所有（C）1996 IBRO。
A long line of studies emphasizes the contribution of serotonergic fibres descending from the rostral ventromedial medulla in the control of spinal nociceptive information processing. A growing body of evidence, however, suggests that the relative contribution of serotonin to the mediation of spinal neuronal activity from the rostral ventromedial medulla may require re-evaluation. It has recently been substantiated that, in addition to the serotonergic fibres, the spinal dorsal horn receives an abundant non-serotonergic projection from the rostral ventromedial medulla. Furthermore, stimulation in the rostral ventromedial medulla could result in a powerful inhibition of nociceptive spinothalamic tract cells without any detectable serotonin release in the dorsal horn. After labelling raphe-spinal axons and axon terminals in the rat by iontophoretic injections of the anterograde axonal tracer Phaseolus vulgaris leucoagglutinin into the central region of the rostral ventromedial medulla (nucleus raphe magnus) and revealing GABA and glycine immunoreactivites of the labelled raphe-spinal terminals and their postsynaptic targets by postembedding immunocytochemical methods, here we demonstrate an extensive GABAergic projection from the rostral ventromedial medulla to the spinal dorsal horn. We show that the majority of the labelled raphe-spinal terminals in laminae I-IIo and IV-V contain GABA and some of the GABA-immunoreactive terminals are also immunoreactive for glycine. We also disclose that GABA-immunoreactive raphe-spinal terminals establish synaptic contacts primarily with GABA- and glycine-negative, presumably excitatory, spinal neurons, including Calbindin-D-28k- as well as parvalbumin-immunoreactive cells in both laminae I-IIo and IV-V.The results suggest that volleys in fibres descending from the rostral ventromedial medulla may evoke GABA release from raphe-spinal terminals, and the released GABA, in some cases probably acting together with glycine, might play a crucial, as yet mostly unidentified, role in the inhibition of nociceptive information processing in the dorsal horn of the spinal cord. Copyright (C) 1996 IBRO.