Ichikawa M, Matsuoka M, Mori Y
Department of Anatomy and Embryology, Tokyo Metropolitan Institute for Neuroscience, Japan.
Synapse. 1995 Oct;21(2):104-9. doi: 10.1002/syn.890210203.
The effects of exposure to soiled bedding on synaptic morphology in the accessory olfactory bulb (AOB) were examined in adult male rats. Forty-day-old male rats were isolated. One group was exposed to bedding soiled by male and female rats (EC). Another group was exposed only to male-soiled bedding (SC). A third group was exposed to clean bedding (IC). After 2 months, the animals were sacrificed for electron microscopy. The size and the numerical density of synapses were measured in the glomerulus and the granule cell layer. In the glomerulus, the mean size of the synapses was significantly greater in the EC than in the IC group, whereas that in the SC group appeared to be intermediate between those in the EC and the IC groups but was not significantly different from those in the EC and the IC groups. There was no statistically significant difference in the density of synapses among the three groups. Synapses in the granule cell layer are classified into two types: 1) perforated synapses, which are characterized by discontinuities in their postsynaptic thickenings, and 2) nonperforated synapses. The mean size of perforated synapses was significantly greater in the EC than in the IC and SC groups; however, no statistically significant difference was observed in the size of nonperforated synapses among the three groups. Moreover, no statistically significant difference was observed in the numerical densities of either perforated or nonperforated synapses among the three groups. These results suggested that exposure to a more complex soiled bedding environment (i.e., to bedding soiled by both male and female rats) can induce greater structural changes of the synapses in the AOB of male adult rats.
在成年雄性大鼠中，研究了接触脏污垫料对副嗅球（AOB）突触形态的影响。将40日龄的雄性大鼠单独饲养。一组暴露于雄性和雌性大鼠弄脏的垫料（EC组）。另一组仅暴露于雄性弄脏的垫料（SC组）。第三组暴露于干净的垫料（IC组）。2个月后，处死动物进行电子显微镜检查。测量肾小球和颗粒细胞层中突触的大小和数量密度。在肾小球中，EC组突触的平均大小显著大于IC组，而SC组的突触大小似乎介于EC组和IC组之间，但与EC组和IC组无显著差异。三组之间突触密度无统计学显著差异。颗粒细胞层中的突触分为两种类型：1）穿孔突触，其特征是突触后增厚处有间断；2）非穿孔突触。EC组穿孔突触的平均大小显著大于IC组和SC组；然而，三组之间非穿孔突触的大小无统计学显著差异。此外，三组之间穿孔或非穿孔突触的数量密度均无统计学显著差异。这些结果表明，暴露于更复杂的脏污垫料环境（即暴露于雄性和雌性大鼠都弄脏的垫料）可诱导成年雄性大鼠AOB中突触发生更大的结构变化。
