Takagi H, Somogyi P, Somogyi J, Smith A D
J Comp Neurol. 1983 Feb 10;214(1):1-16. doi: 10.1002/cne.902140102.
Somatostatin-immunoreactive neurons in the rat neostriatum were studied by correlated light and electron microscopy using the peroxidase-antiperoxidase immunocytochemical technique. Immunoreactivity was localized in neuronal perikarya and processes. The perikarya were of spindle or fusiform shape (average length 16.9 microns) and were found in all parts of the neostriatum. From each neuron there arose two to four straight immunoreactive dendritelike processes, which could frequently be traced as far as about 130 microns from their perikaryon. Immunoreactive varicose axonlike processes were occasionally found, some of which were proximal axons of identified immunoreactive cells. Nine of the light microscopically identified neurons showing somatostatin-immunoreactivity were studied in the electron microscope; two of them had proximal axons with varicosities. Each neuron had an oval or elongated nucleus, which was always indented. These morphological features correspond well to those of certain "medium-size aspiny" neurons classified by Golgi studies. Although the immunoreactive endproduct was diffusely located throughout the neuron, it was characteristically located in the saccules and large granules (diameter 133 nm) of the Golgi apparatus, and large immunoreactive vesicles of similar size to those in the Golgi apparatus frequently occurred in all parts of axon. Very little synaptic input was found on the perikarya and dendrites of somatostatin-immunoreactive neurons. The perikarya and proximal dendrites received both symmetrical and asymmetrical synaptic input, while the distal dendrites usually received boutons that formed asymmetrical contacts. The somatostatin-immunoreactive boutons contained pleomorphic electron-lucent vesicles (diameter 39.3 nm) and a few large immunoreactive granular vesicles; these boutons always formed symmetrical synapses. Their postsynaptic targets were dendritic shafts, spines, and unclassified dendritic profiles. On the other hand, the varicosities of identified proximal axons of somatostatin-positive neurons did not form typical synapses, since they lacked clusters of small vesicles, but some of them were in direct apposition (via membrane specializations) to unlabelled perikarya or dendrites. It is concluded that somatostatin is a useful marker for a particular type of neuron in the neostriatum. The presence of somatostatin immunoreactivity in synaptic boutons is consistent with the view that somatostatin could be a neurotransmitter in the neostriatum.
采用过氧化物酶-抗过氧化物酶免疫细胞化学技术，通过相关的光学显微镜和电子显微镜研究了大鼠新纹状体中生长抑素免疫反应性神经元。免疫反应性定位于神经元胞体和突起。胞体呈纺锤形或梭形（平均长度16.9微米），存在于新纹状体的所有部位。每个神经元发出两到四个笔直的免疫反应性树突状突起，这些突起通常可从其胞体追踪到约130微米远的地方。偶尔会发现免疫反应性曲张轴突样突起，其中一些是已鉴定的免疫反应性细胞的近端轴突。在电子显微镜下研究了9个经光学显微镜鉴定显示生长抑素免疫反应性的神经元；其中两个有带曲张的近端轴突。每个神经元都有一个椭圆形或细长的细胞核，总是有凹陷。这些形态学特征与高尔基研究分类的某些“中等大小无棘”神经元的特征非常吻合。尽管免疫反应终产物在整个神经元中呈弥散分布，但它的特征性位置是在高尔基复合体的扁平囊泡和大颗粒（直径133纳米）中，并且与高尔基复合体中大小相似的大免疫反应性囊泡经常出现在轴突的所有部位。在生长抑素免疫反应性神经元的胞体和树突上发现的突触输入很少。胞体和近端树突接受对称和不对称的突触输入，而远端树突通常接受形成不对称接触的终扣。生长抑素免疫反应性终扣含有多形性电子透亮囊泡（直径39.3纳米）和一些大的免疫反应性颗粒囊泡；这些终扣总是形成对称突触。它们的突触后靶点是树突干、棘突和未分类的树突轮廓。另一方面，生长抑素阳性神经元已鉴定的近端轴突的曲张不形成典型突触，因为它们缺乏小囊泡簇，但其中一些通过膜特化与未标记的胞体或树突直接并置。结论是生长抑素是新纹状体中一种特定类型神经元的有用标记物。生长抑素免疫反应性在突触终扣中的存在与生长抑素可能是新纹状体中的一种神经递质的观点一致。
