Honda T, Semba K
Department of Anatomy and Neurobiology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada.
Brain Res. 1994 Jun 6;647(2):299-306. doi: 10.1016/0006-8993(94)91329-3.
Serotonergic synaptic inputs to cholinergic neurons in the laterodorsal and pedunculopontine tegmental nuclei were examined with pre-embedding dual-label immunoelectron microscopy. Numerous serotonin-immunoreactive axon terminals visualized with a silver-enhanced immunogold method were present in both of these tegmental nuclei. Serotonergic terminals occasionally made synaptic contacts with the soma and proximal dendrites of cholinergic tegmental neurons labelled with a choline acetyltransferase-immunoreactive peroxidase-anti-peroxidase diaminobenzidine reaction product. In the rostralmost region of the laterodorsal tegmental nucleus, a few serotonergic neurons of the dorsal raphe nucleus were interspersed among cholinergic neurons. Some dendrites of these serotonergic neurons appeared to contain synaptic vesicles. Both myelinated and unmyelinated serotonergic axons were present in the mesopontine tegmentum. The presence of serotonergic synapses onto tegmental cholinergic neurons is consistent with previous behavioral and electrophysiological findings suggesting an inhibitory role of serotonin in the induction of rapid eye movement sleep and its phenomenology through an action on cholinergic neurons in the mesopontine tegmentum.
采用包埋前双重标记免疫电子显微镜技术，研究了血清素能突触输入到外侧背核和脚桥被盖核中的胆碱能神经元的情况。用银增强免疫金法观察到，在这两个被盖核中均存在大量血清素免疫反应性轴突终末。血清素能终末偶尔与用胆碱乙酰转移酶免疫反应性过氧化物酶-抗过氧化物酶二氨基联苯胺反应产物标记的胆碱能被盖神经元的胞体和近端树突形成突触联系。在外侧背核的最前端区域，一些中缝背核的血清素能神经元散布于胆碱能神经元之间。这些血清素能神经元的一些树突似乎含有突触小泡。中脑桥被盖部存在有髓鞘和无髓鞘的血清素能轴突。血清素能突触存在于被盖胆碱能神经元上，这与先前的行为学和电生理学研究结果一致，这些研究结果表明血清素通过作用于中脑桥被盖部的胆碱能神经元，在快速眼动睡眠的诱导及其现象学中发挥抑制作用。
