Groves P M, Wilson C J
J Comp Neurol. 1980 Oct 15;193(4):841-52. doi: 10.1002/cne.901930402.
Locus coeruleus of the rat was studied in material prepared by aldehyde-osmium fixation. Cell bodies of locus coeruleus neurons possess large nuclei with a prominent nucleolus, a homogeneous karyoplasm of moderate density, and occasional indentations of the nuclear membrane. The cytoplasm is rich in organelles, including an extensive network of endoplasmic reticulum which forms well organized Nissl bodies. The highly developed Golgi apparatus surrounds the nucleus and extends into large dendritic trunks. In coronal section, cell bodies appear elongated along an approximate dorso-ventral axis, and most dendrites as well as axons appear in cross-section. In parasagittal sections the cells are very elongate, with dendrites and axons in the neuropil mostly cut longitudinally. Thus, locus coeruleus neurons possess disc-shaped dendritic fields parallel to the anterior-posterior axis of the brainstem, with predominantly longitudinal axo-dendritic synaptic configurations. Presynaptic profiles in locus coeruleus neuropil were classified according to the characteristics of their vesicle populations and other features. The most frequently encountered synaptic ending was characterized by small, round, densely packed synaptic vesicles, and comprised approximately 41% of the total sample of 775 synapses. Another group having large, rounded synaptic vesicles, which could be traced in a number of instances to large myelinated axons, accounted for 20% of the sample. Synaptic endings having large, flattened vesicles were also numerous, comprising 23% of the total. Another category of presynaptic endings was identified as those possessing numerous, small, flattened vesicles and comprising about 11% of the sample. Presynaptic endings having many vesicles of mixed sizes accounted for 2% of the total, and another group of the same proportion having small, rounded synaptic vesicles but also an unusually large number of larger, dense-cored vesicles was also present. Two other categories of synaptic endings were encountered, each comprising less than 1% of the total. One of these was derived from small, unmyelinated axons and contained clusters of pleomorphic synaptic vesicles. The other consisted of dendro-dendritic synapses between locus coeruleus neurons and also displayed small clusters of pleomorphic synaptic vesicles near the zone of synaptic apposition. Quantitative analysis revealed that most afferents to the nucleus synapse onto dendrites ranging between 0.5 and 2.5 micrometers in diameter and onto spine-like appendages derived from somata and dendrites. There were no significant differences between different categories of afferent terminals and their spatial distribution onto various postsynaptic targets of locus coeruleus neurons.
采用醛锇固定法制备材料，对大鼠蓝斑进行了研究。蓝斑神经元的胞体具有大核，核仁突出，核质均匀，密度适中，核膜偶尔有凹陷。细胞质富含细胞器，包括广泛的内质网网络，内质网形成了组织良好的尼氏体。高度发达的高尔基体围绕着细胞核并延伸到大的树突干中。在冠状切片中，胞体沿大致的背腹轴呈细长形，大多数树突和轴突呈横断面。在矢状旁切片中，细胞非常细长，神经毡中的树突和轴突大多纵向切断。因此，蓝斑神经元具有与脑干前后轴平行的盘状树突场，主要是纵向的轴突-树突突触构型。根据蓝斑神经毡中突触前成分的囊泡群特征和其他特征进行分类。最常见的突触末梢的特征是小的、圆形的、密集堆积的突触囊泡，在775个突触的总样本中约占41%。另一组具有大的、圆形的突触囊泡，在许多情况下可追溯到有髓大轴突，占样本的20%。具有大的、扁平囊泡的突触末梢也很多，占总数的23%。另一类突触前末梢被鉴定为具有许多小的、扁平囊泡的末梢，约占样本的11%。具有许多大小混合囊泡的突触前末梢占总数的2%，还有一组比例相同的末梢，具有小的、圆形的突触囊泡，但也有异常大量的较大的、有致密核心的囊泡。还遇到了另外两类突触末梢，每类占总数的不到1%。其中一类来自小的无髓轴突，含有多形性突触囊泡簇。另一类由蓝斑神经元之间的树突-树突突触组成，在突触并置区附近也显示有多形性突触囊泡小簇。定量分析表明，大多数传入核的纤维与直径在0.5至2.5微米之间的树突以及源自胞体和树突的棘状附属物形成突触。不同类别的传入终末及其在蓝斑神经元各种突触后靶点上的空间分布之间没有显著差异。
