Gamma-aminobutyrate, gastrin releasing peptide, serotonin, somatostatin, and vasopressin: ultrastructural immunocytochemical localization in presynaptic axons in the suprachiasmatic nucleus.
Gamma-aminobutyrate, gastrin releasing peptide, serotonin, somatostatin, and vasopressin: ultrastructural immunocytochemical localization in presynaptic axons in the suprachiasmatic nucleus.
复制标题
γ-氨基丁酸、胃泌素释放肽、血清素、生长抑素和加压素：视交叉上核突触前轴突的超微结构免疫细胞化学定位。
DOI：
10.1016/0306-4522(86)90037-0
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发表时间：
1986
期刊：
影响因子：
3.3
通讯作者：
vandenPol,AN
中科院分区：
文献类型：
--
作者：
vandenPol,AN
用免疫细胞化学方法观察了下丘脑视交叉上核突触前终扣中的神经活性物质。用包埋前过氧化物酶免疫染色法将含有γ-氨基丁酸、谷氨酸脱羧酶、垂体后叶素/血管加压素、胃泌素释放肽/铃蟾肽、生长抑素和5-羟色胺的轴突终扣定位于下丘脑视交叉上核内。突触接触之间发现含有这些物质和突触后结构的终扣。虽然突触形态存在一些变化，但大多数免疫反应接触是对称型的。以前的工作表明，神经活性肽可能在致密核心囊泡中以最高浓度存在，为了检查氨基酸抑制性递质γ-氨基丁酸的亚细胞定位，将包埋前过氧化物酶的超微结构免疫细胞化学与包埋后胶体金的免疫细胞化学进行了比较。超低温蛋白切片还用于γ-氨基丁酸和谷氨酸脱羧酶免疫反应性的超微结构定位。包埋前的过氧化物酶，γ-氨基丁酸和谷氨酸脱羧酶的免疫反应，发现整个细胞质的免疫反应性终扣时，包埋后的胶体金免疫染色，标签被发现在含有小透明囊泡的区域，并在线粒体的免疫反应性轴突。在本研究中使用的稀释度下，未发现强免疫反应性γ-氨基丁酸树突、形成不对称突触的终扣和细胞体。包埋前和包埋后免疫染色之间的差异可能是由于包埋前免疫染色过程中抗血清穿透所必需的轻度固定和膜损伤引起的抗原和标记扩散。这些结果表明，γ-氨基丁酸、胃泌素释放肽、生长抑素和血管加压素包含在与视交叉上核的神经元接触的轴突中，并且在这里可以起到神经递质的作用。由于所有这些物质也可以定位在视交叉上核内的胞体中，因此很有可能至少一些含有这些物质的免疫反应性的轴突可能参与视交叉上核内神经元之间的局部回路相互作用。
An ultrastructural immunocytochemical study was undertaken to identify neuroactive substances contained in presynaptic boutons in the hypothalamic suprachiasmatic nucleus. Axonal boutons containing immunoreactive γ-aminobutyrate, glutamate decarboxylase, neurophysin/vasopressin, gastrin releasing peptide/bombesin, somatostatin and serotonin were localized within the hypothalamic suprachiasmatic nucleus with pre-embedding peroxidase immunostaining. Synaptic contacts were found between boutons containing each of these substances and postsynaptic structures. While some variation in synaptic morphology existed, most of the immunoreactive contacts were of the symmetrical type. Previous work has indicated that neuroactive peptides may be found in highest concentrations in dense-core vesicles, to examine the subcellular localization of the amino acid inhibitory transmitter γ-aminobutyrate, ultrastructural immunocytochemistry with pre-embedding peroxidase was compared with post-embedding immunocytochemistry with colloidal gold. Ultracryothin sections were also used for ultrastructural localization of γ-aminobutyrate and glutamate decarboxylase immunoreactivity. Both γ-aminobutyrate and glutamate decarboxylase immunoreactivity were found throughout the cytoplasm of immunoreactive boutons when pre-embedding peroxidase was used; with post-embedding colloidal gold immunostaining, label was found over areas containing small clear vesicles, and over mitochondria of immunoreactive axons. At the dilutions used in this study, strongly immunoreactive γ-aminobutyrate dendrites, boutons forming asymmetrical synapses, and cell bodies were not found. Differences between pre-embedding and post-embedding immunostaining may be due to antigen and label diffusion caused by mild fixation and membrane damage necessary for antisera penetration during pre-embedding immunostaining.These results suggest that γ-aminobutyrate, gastrin releasing peptide, somatostatin and vasopressin are contained in axons making contact with neurons of the suprachiasmatic nucleus, and may function as neurotransmitters here. Since all of these substances can also be localized in perikarya within the suprachiasmatic nucleus, there is a strong possibility that at least some of the axons containing immunoreactivity for each of these substances may be involved in local circuit interactions between neurons within the suprachiasmatic nucleus.