Kosaka K, Heizmann C W, Kosaka T
Department of Anatomy and Neurobiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Exp Brain Res. 1994;99(2):191-204. doi: 10.1007/BF00239586.
The laminar distribution and morphological features of parvalbumin-immunoreactive [PV(+)] neurons, one of the subpopulations of GABAergic neurons, were studied in the rat olfactory bulb at a light microscopic level. In the main olfactory bulb of adult rats, PV(+) neurons were mainly located in the external plexiform layer (EPL), and a few were scattered in the glomerular layer (GL), mitral cell layer (ML), and granule cell layer (GRL); whereas PV(+) neurons were rarely seen in the accessory olfactory bulb. The inner and outer sublayers of the EPL (ISL and OSL) appeared to be somewhat different in the distribution of PV(+) somata and features of PV(+) processes. PV(+) somata were located throughout the OSL, and PV(+) processes intermingled with one another, making a dense meshwork in the OSL; whereas, in the ISL, PV(+) somata were mainly located near the inner border of the EPL, and PV(+) processes made a sparser meshwork than that in the OSL. PV(+) neurons in the EPL were apparently heterogeneous in their structural features and appeared to be classifiable into several groups. Among them there appeared five distinctive types of PV(+) neurons. The most prominent group of PV(+) neurons in the OSL were superficial short-axon cells, located in the superficial portion of this sublayer and giving rise to relatively thick processes, in horizontal or oblique directions, which usually bore spines and varicosities. Another prominent group of PV(+) neurons extended several short, branched dendrites with spines and varicosities, which appeared to intermingle with one another, making a relatively small, spherical or ovoid dendritic field around the cell bodies; most of them resembled Van Gehuchten cells reported in previous Golgi studies. A third distinctive and most numerous group of PV(+) neurons were of the multipolar type; their somata and processes were located throughout the EPL. Their relatively smooth processes with frequent varicosities and a few spines were extended horizontally or diagonally throughout the EPL. A fourth group, which could be a subtype of the multipolar type, were located in or just above th ML and extended several thin, smooth dendrites in the EPL, some of which appeared to reach the border between the GL and EPL. Occasionally, axon-like processes arose from their cell bodies and extended into the ML. This fourth type of PV(+) neuron was named inner short-axon cells. A fifth group of neuron was located in the ML; processes of these neurons were extended horizontally, so they were named inner horizontal cells.(ABSTRACT TRUNCATED AT 400 WORDS)
在光学显微镜水平下，研究了大鼠嗅球中γ-氨基丁酸能神经元亚群之一的小白蛋白免疫反应阳性（PV(+)）神经元的层状分布和形态特征。在成年大鼠的主嗅球中，PV(+)神经元主要位于外丛状层（EPL），少数散在于肾小球层（GL）、二尖瓣细胞层（ML）和颗粒细胞层（GRL）；而在副嗅球中很少见到PV(+)神经元。EPL的内、外亚层（ISL和OSL）在PV(+)胞体的分布和PV(+)突起的特征上似乎有所不同。PV(+)胞体遍布OSL，PV(+)突起相互交织，在OSL中形成密集的网络；而在ISL中，PV(+)胞体主要位于EPL的内边界附近，PV(+)突起形成的网络比OSL中的稀疏。EPL中的PV(+)神经元在结构特征上明显异质，似乎可分为几组。其中出现了五种不同类型的PV(+)神经元。OSL中最突出的一组PV(+)神经元是浅层短轴突细胞，位于该亚层的浅层，发出相对较粗的突起，呈水平或倾斜方向，通常带有棘突和曲张。另一组突出的PV(+)神经元伸出几个有棘突和曲张的短分支树突，这些树突似乎相互交织，在细胞体周围形成相对较小的球形或卵形树突场；它们中的大多数类似于先前高尔基研究中报道的范·盖胡滕细胞。第三组独特且数量最多的PV(+)神经元是多极型；它们的胞体和突起遍布EPL。它们相对光滑的突起有频繁的曲张和一些棘突，在EPL中水平或对角延伸。第四组可能是多极型的一个亚型，位于ML内或ML上方，在EPL中伸出几个细的、光滑的树突，其中一些似乎到达GL和EPL之间的边界。偶尔，轴突样突起从它们的细胞体发出并延伸到ML中。第四种类型的PV(+)神经元被命名为内侧短轴突细胞。第五组神经元位于ML；这些神经元的突起水平延伸，因此被命名为内侧水平细胞。（摘要截断于400字）
