Comparative Analyses of the Main Olfactory Bulb : Rodent and Insectivore

主要嗅球的肾小球被认为是嗅觉信息处理的功能单位。我们证实了小鼠肾小球的间隔性组织以及1型和2型肾小球周围细胞的存在。与大鼠肾小球周围细胞相似，酪氨酸羟化酶(TH)阳性细胞为1型，GAD/GABA阳性。另一方面，Calbindin D28k(CB)阳性和Calretinin(CR)阳性细胞均为2型小球周围细胞，但与GAD/GABA阴性的大鼠不同，所有Calbindin D28k阳性的球周细胞和50%的Calretinin阳性的球周细胞均为GAD/GABA阳性。因此，GAD/GABA阳性细胞包括1型和2型小球周围细胞。肾小球旁一氧化氮合酶阳性细胞被认为是大鼠肾小球周围1型细胞的一个亚群，区别于CR阳性细胞和CB阳性细胞。然而，在小鼠中，大约70%的NOS阳性细胞是Calretinin阳性的，50%的CR阳性细胞是NOS阳性的。在此，我们揭示了小球周围细胞化学性质的显著物种差异，并提示小鼠主嗅球的细胞组织不能从大鼠的组织结构中推断出来。此外，我们还报道了一氧化氮合酶阳性神经元和PV阳性神经元在小鼠中的准确分布和特征。

Glomeruli of the main olfactory bulb (MOB) are now considered to serve as functional units in the olfactory information processing. We confirmed the compartmental organization of the glomerulus and the presence of both type 1 and 2 periglomerular cells in the mice. Similar to rat periglomerular cells, the tyrosine hydroxylase (TH) -positive cells were type 1 and GAD/GABA-positive. On the other hand, both the calbindin D28k (CB) -positive and calretinin (CR) -positive cells were type 2 periglomerular cells, but in contrast to those in rats, which are GAD/GABA-negative, all of the calbindin D28k-positive periglomerular cells and 50% of the calretinin-positive periglomerular cells were GAD/GABA-positive. The GAD/GABA-positive cells thus included both type 1 and type 2 periglomerular cells. Juxtaglomerular NOS-positive cells have been proposed as a subgroup of type 1 periglomerular cells that are separate from the CR-positive and CB-positive cells in rats. However, in the mice, about 70% of the NOS-positive cells were calretinin-positive, and 50% of the CR-positive cells were NOS-positive. We herein reveal the significant species differences in the chemical properties of periglomerular cells and suggest that the cellular organization of the mouse main olfactory bulb cannot be extrapolated from that of rats.Furthermore, we reported the precise distribution and characteristic features of NOS-positive and PV-positive neurons in the mouse MOB.