Hisano S, Chikamori-Aoyama M, Katoh S, Maegawa M, Daikoku S
Histochemistry. 1987;86(6):573-8. doi: 10.1007/BF00489549.
By applying a double-immunolabeling technique to preembedded tissue preparations, we demonstrated the existence of serotoninergic innervation to neurons containing vasoactive intestinal polypeptide (VIP) in the rat suprachiasmatic nucleus (SCN). Immunoreactivity for serotonin and VIP was revealed by the presence of diaminobenzidine (DAB) reaction products and silver-intensified DAB reaction products, respectively; in a further stage, the silver grains were substituted with gold particles. DAB reaction products were precipitated on the surface of vesicular structures, while gold particles were scattered diffusely throughout the neuroplasma at various densities. Serotoninergic axons were numerous and closely packed together, occasionally forming synaptic junctions with gold-labeled VIP-containing neurons. At these synaptic junctions, small vesicular structures accumulated to form a coat under the presynaptic membrane, and the postsynaptic membrane was lined with a homogeneous accumulation of fine deposits. This postsynaptic apparatus varied in appearance; some parts were flat and thin, while others were of irregular thickness. Serotoninergic fibers also formed synaptic junctions with unidentified neurons, in which postsynaptic membrane specialization was also observable. As VIP-containing neurons are known to be synapsed by somatostatin (SRIH)-containing neurons, their regulation must involve both serotonin and SRIH at least.
通过对预包埋组织切片应用双免疫标记技术，我们证实了大鼠视交叉上核（SCN）中含血管活性肠肽（VIP）的神经元存在5-羟色胺能神经支配。5-羟色胺和VIP的免疫反应性分别通过二氨基联苯胺（DAB）反应产物和银增强的DAB反应产物来显示；在进一步的步骤中，银颗粒被金颗粒替代。DAB反应产物沉淀在囊泡结构的表面，而金颗粒以不同密度弥漫性地散布于整个神经浆中。5-羟色胺能轴突众多且紧密排列在一起，偶尔与金标记的含VIP神经元形成突触连接。在这些突触连接处，小囊泡结构聚集在突触前膜下方形成一层，突触后膜则有均匀堆积的细小沉积物。这种突触后结构外观各异；有些部分扁平且薄，而其他部分厚度不规则。5-羟色胺能纤维也与未识别的神经元形成突触连接，在其中也可观察到突触后膜特化。由于已知含VIP的神经元与含生长抑素（SRIH）的神经元形成突触，它们的调节至少必须涉及5-羟色胺和SRIH两者。
