Standaert D G, Watson S J, Houghten R A, Saper C B
J Neurosci. 1986 May;6(5):1220-6. doi: 10.1523/JNEUROSCI.06-05-01220.1986.
The parabrachial nucleus (PB) is the major relay for ascending visceral afferent information from the nucleus of the solitary tract to the forebrain. We have recently found that PB in the rat also receives a substantial afferent projection from neurons in the marginal zone of the entire length of the spinal and trigeminal dorsal horn. Immunoreactive perikarya stained with antisera against several neuropeptides--including dynorphin, enkephalins, and substance P--have been identified in the marginal zone. We therefore investigated the chemical specificity of the spinoparabrachial projection by combining fluorescent retrograde tracing with immunofluorescence for substance P, dynorphin A1-17, met-enkephalin, and two enkephalin precursor fragments (proenkephalin 192-203 and peptide E). Following PB injections of fluorescent dyes, about half of the retrogradely labeled neurons in the marginal zone stained with antisera against either dynorphin or enkephalin series peptides. Elution-restaining experiments indicated that the dynorphin- and enkephalin-immunoreactivities were contained within separate populations of marginal zone neurons. We could not identify any substance P-immunoreactive perikarya in the marginal zone, but substance P-immunoreactive fibers were seen in close apposition to retrogradely labeled, opioid-immunoreactive cell bodies and dendrites. These results indicate that the dynorphin- and enkephalin-immunoreactive perikarya in the marginal zone of the dorsal horn represent independent neuronal populations. These opioid-immunoreactive neurons, which are believed to have extensive local collateral connections, are the main source of a long ascending projection to the parabrachial nucleus in the rat. Furthermore, opioid neurons in the marginal zone may receive substance P-immunoreactive primary sensory afferents.
臂旁核（PB）是从孤束核向上传递内脏传入信息至前脑的主要中继站。我们最近发现，大鼠的臂旁核还接收来自脊髓和三叉神经背角全长边缘区神经元的大量传入投射。在边缘区已鉴定出用抗几种神经肽（包括强啡肽、脑啡肽和P物质）的抗血清染色的免疫反应性胞体。因此，我们通过将荧光逆行追踪与P物质、强啡肽A1-17、甲硫脑啡肽和两种脑啡肽前体片段（前脑啡肽192-203和肽E）的免疫荧光相结合，研究了脊髓臂旁投射的化学特异性。向臂旁核注射荧光染料后，边缘区约一半逆行标记的神经元用抗强啡肽或脑啡肽系列肽的抗血清染色。洗脱再染色实验表明，强啡肽和脑啡肽免疫反应性存在于边缘区神经元的不同群体中。我们在边缘区未发现任何P物质免疫反应性胞体，但可见P物质免疫反应性纤维与逆行标记的阿片样物质免疫反应性细胞体和树突紧密相邻。这些结果表明，背角边缘区的强啡肽和脑啡肽免疫反应性胞体代表独立的神经元群体。这些阿片样物质免疫反应性神经元被认为具有广泛的局部侧支连接，是大鼠向臂旁核长距离上行投射的主要来源。此外，边缘区的阿片样物质神经元可能接收P物质免疫反应性初级感觉传入。
