Graziano Alessandro, Jones Edward G
Center for Neuroscience, University of California Davis, Davis, California 95616, USA.
J Neurosci. 2004 Jan 7;24(1):248-56. doi: 10.1523/JNEUROSCI.4122-03.2004.
The relay of pain fibers from the spinal and medullary dorsal horn in the thalamus has become a controversial issue. This study analyzed the relationship of fibers arising in lamina I to nuclei in and around the caudal pole of the ventral posterior nuclear complex and especially to a zone of calbindin-dense immunoreactivity (VMpo) identified by some authors as the sole thalamic relay for these fibers. We show that the densest zone of calbindin immunoreactivity is part of a more extensive, calbindin-immunoreactive region that lies well within the medial tip of the ventral posterior medial nucleus (VPM), as delineated by other staining methods, and prove that the use of different anti-calbindin antibodies cannot account for differences in interpretations of the organization of the posterior thalamic region. By combining immunocytochemical staining with anterograde tracing from injections involving lamina I, we demonstrate widespread fiber terminations that are not restricted to the calbindin-rich medial tip of VPM and show that the lamina I arising fibers are not themselves calbindin immunoreactive. This study disproves the existence of VMpo as an independent thalamic pain nucleus or as a specific relay in the ascending pain system.
来自脊髓和延髓背角的痛觉纤维在丘脑的中继已成为一个有争议的问题。本研究分析了I层产生的纤维与腹后核复合体尾极及其周围核团的关系，特别是与一些作者确定为这些纤维唯一丘脑中继的钙结合蛋白密集免疫反应区（VMpo）的关系。我们表明，钙结合蛋白免疫反应最密集的区域是一个更广泛的钙结合蛋白免疫反应区域的一部分，该区域位于腹后内侧核（VPM）内侧尖端内，正如其他染色方法所描绘的那样，并证明使用不同的抗钙结合蛋白抗体不能解释对丘脑后区组织结构解释的差异。通过将免疫细胞化学染色与来自涉及I层注射的顺行追踪相结合，我们证明了广泛的纤维终末并不局限于富含钙结合蛋白的VPM内侧尖端，并表明I层产生的纤维本身没有钙结合蛋白免疫反应性。本研究反驳了VMpo作为一个独立的丘脑痛觉核或作为上行痛觉系统中特定中继的存在。
