Murakawa R, Kosaka T
Department of Anatomy and Neurobiology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan.
J Comp Neurol. 2001 Jan 1;429(1):113-26. doi: 10.1002/1096-9861(20000101)429:1<113::aid-cne9>3.0.co;2-d.
We have recently revealed that large multipolar neurons, presumed mossy cells in the hamster dentate gyrus (DG), were calretinin (CR)-immunoreactive (IR) at the ventral level, although these neurons were CR-negative at the dorsal level. In the present study, we confirmed this identification with several methods and analyzed structural features of hamster mossy cells in detail. Golgi impregnationi and intracellular Lucifer yellow labeling studies revealed that mossy cells in the hamster dentate hilus had extraordinarily prominent thorny excrescences on their somata as well as on their proximal dendrites. Mossy cells exhibited dorsoventral differences in their structural features; proximal dendrites of single mossy cells were fewer, and thorny excrescences were larger and more complicated at the dorsal level than at the ventral level. Electron microscopic serial section three-dimensional reconstructions revealed that somatic thorny excrescences consisted of large and complicated spines, which received numerous asymmetrical synapses from mossy fiber terminals. In addition, our confocal laser scanning microscopic observations also revealed many glutamic acid decarboxylase-immunoreactive punctae abutting the mossy cell somata and dendrites. Our present and previous observations revealed the structural features of hamster mossy cells and their differences along the dorsoventral axis and further indicated that mossy cells were prominently different in their chemical and morphological features among species.
我们最近发现，仓鼠齿状回（DG）中假定为苔藓细胞的大型多极神经元在腹侧水平呈钙视网膜蛋白（CR）免疫反应性（IR），尽管这些神经元在背侧水平呈CR阴性。在本研究中，我们用几种方法证实了这一鉴定，并详细分析了仓鼠苔藓细胞的结构特征。高尔基染色和细胞内荧光黄标记研究表明，仓鼠齿状回门区的苔藓细胞在其胞体以及近端树突上有异常突出的棘状赘生物。苔藓细胞在结构特征上表现出背腹差异；单个苔藓细胞的近端树突较少，背侧水平的棘状赘生物比腹侧水平的更大且更复杂。电子显微镜连续切片三维重建显示，胞体棘状赘生物由大而复杂的棘组成，这些棘接受来自苔藓纤维终末的大量不对称突触。此外，我们的共聚焦激光扫描显微镜观察还显示，许多谷氨酸脱羧酶免疫反应性斑点紧靠苔藓细胞的胞体和树突。我们目前和先前的观察揭示了仓鼠苔藓细胞的结构特征及其沿背腹轴的差异，并进一步表明苔藓细胞在不同物种间的化学和形态特征存在显著差异。
