棕色田鼠脑和行为不同发育阶段副嗅球和主嗅球的细胞活动

本文运用免疫组化显示Fos蛋白的方法首次研究了棕色田鼠脑和行为不同发育阶段副嗅球和主嗅球的细胞活动。当不同年龄阶段的幼鼠同时暴露于自己家庭的熟悉底物和另一家庭的陌生底物时 ,嗅闻和呆在自己熟悉底物上的时间较多 ,直到产后 15d、 2 0d和 2 5d时 ,幼鼠探究不同底物的行为显示出显著性差异。脑的大小随着日龄增加而增加 ,但从产后 1到 15d ,脑重、脑宽和嗅球大小随着日龄增加特别显著。当不同日龄幼鼠暴露于陌生底物或者暴露于自己的熟悉底物时 ,从产后 5到 15日龄 ,主嗅球僧帽细胞层、颗粒细胞层、副嗅球僧帽细胞层和颗粒细胞层Fos免疫阳性细胞随着日龄明显增加 ,但直到 15和 30日龄时 ,和对照组相比 ,陌生底物可引起幼鼠主嗅球Fos免疫阳性细胞明显增加 ,从 2 0日龄起 ,陌生底物可引起副嗅球Fos免疫阳性细胞明显增加。主嗅球颗粒细胞层Fos免疫阳性细胞随着日龄的增加从边缘到中心逐渐出现 ,而副嗅球Fos免疫阳性细胞随着日龄的增加从顶部到底部逐渐出现。以上结果说明产后第 1d到 15d左右可能是棕色田鼠脑结构发育的重要阶段 ,而从此以后棕色田鼠主嗅球和副嗅球就具有区别熟悉气味和陌生气味的能力 ,表明棕色田鼠行为、脑发育和细胞活动间有紧密关系

Cellular activities of AOB, MOB in different behavior and brain developmental stages of mandarin voles Microtus mandarinus

Cellular activities of accessory olfactory bulbs (AOB) and main olfactory bulbs (MOB), behaviors and brain size of mandarin voles Microtus mandarinus were investigated at different postnatal developmental stages. A pup exposed to both its own familiar colony odor and a novel colony odor simultaneously spent longer time sniffing and walking cross substrate of its own colony in its postnatal days. Until postnatal days 15, 20 and 25, pups investigated their own colony substrate for significantly longer duration. Brain sizes of pups increased daily from birth, but from postnatal day 1 to 15, brain weight, cerebrum size and olfactory bulb size augmented more obviously. When pups were exposed to novel colony substrates or to their own colony substrates (control groups), the number of Fos immunopositive cells in both the mitral and granule layers of MOB, Fos-ir neurons in granule layer of AOB, numbers of activated cells in the mitral cell layer of AOB all increased significantly from postnatal days 5 to 15. But from 15 days age to 30 days age, exposure of pups to novel colony substrates caused significantly more c-Fos activation than control groups in mitral and granule cell layers of MOB. Furthermore, from postnatal day 20 to 30, numbers of activated cells in the granule and mitral layers of AOB were significantly greater than those in control groups. Dense Fos-ir cells in granule layer of MOB appeared from the periphery to the core of MOB from birth to 30 days of age while dense Fos-ir cells appeared from apical to bottom region of AOB from birth. This result showed that the period from birth to about 15 days of age is a very important phase for structural development of the brain. MOB began to show obvious ability to discriminate strange and familiar odours from 15 days of age while AOB began to exhibit significant ability from 20 days of age. The results also exhibited very close relationships among behaviors, brain development and cellular activities.