Yokota Shigefumi, Tsumori Toshiko, Ono Katsuhiko, Yasui Yukihiko
Department of Anatomy and Morphological Neuroscience, Shimane Medical University, Izumo 693-8501, Japan.
Brain Res. 2004 Jan 2;995(1):118-30. doi: 10.1016/j.brainres.2003.09.067.
After ipsilateral injections of biotinylated dextran amine (BDA) into the Kölliker-Fuse (KF) nucleus and cholera toxin B subunit (CTb) into the ventral horn in C4 to C5 segments of the spinal cord, an overlapping distribution of BDA-labeled axon terminals and CTb-labeled neurons was found in the rostral ventral respiratory group (rVRG) region ipsilateral to the injection sites. After ipsilateral injections of BDA into the KF and Fluoro-Gold (FG) into the ventral horn in C4 to C5 segments of the spinal cord, BDA-labeled axons were found to make asymmetrical synapses with the somata and dendrites of FG-labeled neurons within the neuropil of the rVRG region. Using retrograde tracing combined with immunohistochemistry for phosphate-activated glutaminase (PAG), we observed that as many as 72% of the rVRG neurons projecting to the PhN were immunoreactive for PAG and that approximately 62% and 75% of the KF neurons projecting respectively to the rVRG region and PhN contain PAG immunoreactivity. Using anterograde tracing combined with immunohistochemistry for vesicular glutamate transporter 2 (VGluT2), we further demonstrated that the KF axon terminals in the rVRG and PhN regions as well as the rVRG axon terminals in the PhN region contain VGluT2 immunoreactivity. The present results suggest that the glutamatergic pathways from the KF to the PhN directly and indirectly via the rVRG region may exist and underlie the inspiratory responses that are elicited by activation of the KF neurons.
在将生物素化葡聚糖胺（BDA）同侧注射到柯利克 - 福斯（KF）核，并将霍乱毒素B亚基（CTb）注射到脊髓C4至C5节段的腹角后，在注射部位同侧的吻侧腹侧呼吸组（rVRG）区域发现了BDA标记的轴突终末和CTb标记的神经元的重叠分布。在将BDA同侧注射到KF并将氟金（FG）注射到脊髓C4至C5节段的腹角后，发现BDA标记的轴突与rVRG区域神经毡内FG标记神经元的胞体和树突形成不对称突触。使用逆行追踪结合磷酸激活谷氨酰胺酶（PAG）的免疫组织化学，我们观察到投射到延髓旁核（PhN）的rVRG神经元中多达72%对PAG有免疫反应，并且分别投射到rVRG区域和PhN的KF神经元中约62%和75%含有PAG免疫反应性。使用顺行追踪结合囊泡谷氨酸转运体2（VGluT2）的免疫组织化学，我们进一步证明rVRG和PhN区域的KF轴突终末以及PhN区域的rVRG轴突终末含有VGluT2免疫反应性。目前的结果表明，从KF到PhN可能存在直接和间接通过rVRG区域的谷氨酸能通路，并构成KF神经元激活所引发的吸气反应的基础。
