Sasek C A, Zigmond R E
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115.
J Comp Neurol. 1989 Feb 22;280(4):522-32. doi: 10.1002/cne.902800403.
Electrical stimulation of the preganglionic cervical sympathetic trunk causes an increase in dopa synthesis in the postganglionic neurons in the superior cervical ganglion (SCG). This transsynaptic biochemical effect can be blocked only partially by cholinergic antagonists, suggesting the involvement of a noncholinergic preganglionic sympathetic neurotransmitter(s). A survey of a large number of possible candidates for this neurotransmitter revealed that, in addition to cholinergic agonists, only a small group of peptides (all members of the secretin-glucagon family) stimulated dopa synthesis in the SCG. The effective peptides included vasoactive intestinal peptide (VIP), peptide histidine isoleucine amide (PHI), and secretin. Consequently we looked for the presence of immunoreactivities for these three peptides in the SCG. VIP- and PHI-like immunoreactive fibers were found in the SCG and in its major pre- and postganglionic nerve trunks. The distributions of the two immunoreactivities were very similar. Immunoreactive fibers were seen both singly and in bundles. In some instances, fibers were found apposed to neuronal cell bodies in the ganglion, and occasionally dense plexuses of fibers were found surrounding the neurons. In addition, punctate immunoreactive profiles were found apposed to the neurons in what appeared to be terminal fields. A small number of immunoreactive neuronal cell bodies were also seen in the ganglion. In a few instances, it was possible to establish, in serial sections, that the same cell body was immunostained with both VIP and PHI antisera. No secretin like-immunoreactive fibers or cells were observed. The presence of VIP-like and PHI-like-immunoreactive fibers in the cervical sympathetic trunk and in the SCG strengthens the possibility that these peptides, or a related molecule(s), serve as preganglionic neurotransmitters in this ganglion.
对颈上交感神经节前干进行电刺激会导致颈上神经节（SCG）节后神经元中多巴胺合成增加。这种跨突触生化效应仅能被胆碱能拮抗剂部分阻断，这表明存在一种非胆碱能的节前交感神经递质。对大量可能的该递质候选物进行研究后发现，除胆碱能激动剂外，只有一小类肽（均为促胰液素 - 胰高血糖素家族成员）能刺激SCG中的多巴胺合成。有效的肽包括血管活性肠肽（VIP）、肽组氨酸异亮氨酸酰胺（PHI）和促胰液素。因此，我们研究了SCG中这三种肽的免疫反应性。在SCG及其主要的节前和节后神经干中发现了VIP样和PHI样免疫反应性纤维。两种免疫反应性的分布非常相似。免疫反应性纤维既可见单个的，也可见成束的。在某些情况下，可看到纤维与神经节中的神经元细胞体相邻，偶尔还能发现围绕神经元的密集纤维丛。此外，在看似终末区的部位发现有散在的免疫反应性点状结构与神经元相邻。在神经节中也可见少数免疫反应性神经元细胞体。在少数情况下，通过连续切片可以确定同一个细胞体同时被VIP和PHI抗血清免疫染色。未观察到促胰液素样免疫反应性纤维或细胞。颈交感神经干和SCG中存在VIP样和PHI样免疫反应性纤维，这增加了这些肽或相关分子在该神经节中作为节前神经递质的可能性。
