Target Specificity of Projections from Postganglionic Sympathetic Neurons Innervated by Enkephalin Containing Preganglionic Fibers.

已知交感神经系统的神经元除含有去甲肾上腺素（NA）、乙酰胆碱等经典神经递质外，还含有多种神经肽。在目前的研究中，我们研究了狗的交感神经细胞和它们的目标之间的特定连接编码与某些神经肽。通过快速蓝色示踪技术和免疫组织化学分析，发现：1。脑啡肽(ENK)-免疫反应（IR）纤维选择性分布于星状神经节和L_6-S_1交感神经节，起源于脊髓中外侧核的神经节前神经元。ENK-1R纤维围绕血管活性肠肽(VIP)/降钙素基因相关肽(CCRP)/ P物质(SP)-IR非na神经节细胞形成篮状末梢。许多ENK-1R末端与节后神经元体形成直接接触，也形成不对称的轴突-树突突触。星状神经节的VIP/CGRP/SP-IR神经节后神经元选择性地支配足部汗腺。因此，靶特异性连接，即ENK含有节前神经元-> VIP/CGRP/SP含有节后神经元->汗腺，被证实。在另一项实验中，我们展示了犬喉中具有不同化学密码的内在神经节神经元的目标特异性投射。

It has been known that neurons of sympathetic nervous system contain many kinds of neuropeptides in addition to the classical neurotransmitter such Noradrenaline (NA) or acetylcholine. In the present study we investigated specific connections coded with certain neuropeptides between sympathetic nerve cells and their targets in the dog. By use of the fast blue tracing technique and immunohistochemistry, it was revealed that :1. Enkephalin (ENK)-Immunoreactive (IR) fibers were selectively distributed in the stellate and L_6-S_1 sympathetic ganglia, and were originated from preganglionic neurons in the intermediolateral nucleus of spinal cord.2. The ENK-1R fibers surrounded Vasoactive Intestinal Peptide (VIP)/Calcitonin Gene-Related Peptide (CCRP)/Substance P (SP)-IR non-NA ganglionic cells and formed a basket-like terminal.3. Many ENK-1R terminals formed direct contacts with somata of postganglionic neurons and also made asymmetrical axo-dendritic synapses.4. The VIP/CGRP/SP-IR postganglionic neurons in the stellate ganglion innervated selectively to the sweat glands of the footpads.Thus, a target specific connection, i. e., the ENK containing preganglionic neurons -> VIP/CGRP/SP containing postganglionic neurons -> sweat glands, was demonstrated.In another experiment, we demonstrated target-specific projections of intrinsic ganglionic neurons with different chemical codes in the canine larynx.