Analyses on the juxtaglomerular neurons of the olfactory bulb : 2 types of periglomerular cells

嗅球是嗅觉的第一中枢，其肾小球被认为是嗅觉信息处理的重要功能单位。在本研究中，我们研究了以下三点。(1)1型和2型肾小球周围细胞有轴突吗？我们使用1型和2型肾小球周围细胞以及轴突起始节段的化学标记物的抗体，如AnklidG、Nav和β IV-血影蛋白，应用多重荧光免疫染色。共聚焦激光扫描观察到大型酪氨酸羟化酶（TH）阳性的GABA能肾小球神经元、一氧化氮合酶（NOS）阳性的外丛状细胞和表达NOS、钙结合蛋白（calbindin）和小清蛋白（PV）的短轴突细胞。然而，大多数对嗅球小球神经元的分析：2种球周细胞球周细胞没有显示化学鉴定的轴突起始段，表明这些球周细胞是 ...更多信息 轴突的(2)TH阳性GABA能肾小球神经元是成年期产生的主要神经元之一。另一方面，TH阳性神经元有两种类型，大的和小的，并且如我们先前所揭示的，大类型的TH阳性神经元显示长的延伸轴突突起到远侧肾小球，形成抑制性联合系统。在本研究中，我们确定了何时两种类型的TH阳性神经元出生，以及成人产生的TH阳性神经元是否包括两种类型。在不同发育阶段注射BrdU;产前期（E13，E17），新生儿（P3）和幼年或成年（P4 w或8 w）。结果表明，大、小TH阳性神经元均在出生前和新生儿期产生。但只有少数TH阳性神经元是成体神经元。(3)我们在外丛状层的轴突PV阳性GABA能神经元的树突节段上发现了特定的轴突起始节样或Ranvier样节点的“热点”。这些热点表达了轴突起始段的化学标记，并进一步显示了轴突起始段特有的超微结构特征，即膜底被。因此，这些热点被认为是尖峰产生的网站。少

In the olfactory bulb, the first center of the olfaction, the glomerulus is considered as a functional unit and thus to be important in the olfactory information processing. In the present study we examined following three points. (1) Do the periglomerular cells, type 1 and type 2, have axons? We applied multiple fluorescent immunostaining using antibodies of chemical markers for type 1 and 2 periglomerular cells as well as for axon initial segments, such as AnkyrinG, Nav, and βIV-spectrin. The confocal laser scanning observations revealed that large type of tyrosine hydroxylase (TH) positive GABAergic juxtaglomerular neurons, nitric oxide synthase (NOS) positive external tufted cells and short-axon cells expressing NOS, calbindin and parvalbumin (PV). However, most of Analyses on the juxtaglomerular neurons of the olfactory bulb : 2 types of periglomerular cells periglomerular cells did not show the chemically identified axon initial segments, indicating those periglomerular cells are … More anaxonic. (2) As well known TH positive GABAergic juxtaglomerular neurons are one of major groups of neurons generated even in adult period. On the other hand, there two types of TH positive neurons, large and small ones, and as we previously revealed the large type of TH positive neurons show long extending axonal processes to distant glomeruli making the inhibitory association system. In the present study we determined when both types of TH positive neurons are born and whether adult-generated TH positive neurons include both types. BrdU were injected at various developmental stages; prenatal period (E13, E17), neonate (P3) and juvenile or adult (P4w or 8w). This analysis revealed that both large and small TH positive neurons generated during prenatal and neonate periods. But only small type of TH positive neurons are adult-generated neurons. (3) We found particular axon initial segment-like or node of Ranvier-like sites "hot spots" on the dendritic segments of anaxonic PV positive GABAergic neurons in the external plexiform layer. These hot spots expressed chemical markers for axon initial segments and furthermore showed the ultrastructural feature characteristic to axon initial segment, membrane undercoating. Thus these hot spots are supposed to be the spike generating sites. Less