Age and sex differences in mitotic activity within the zebra finch telencephalon
Age and sex differences in mitotic activity within the zebra finch telencephalon
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DOI：
10.1523/jneurosci.22-10-04080.2002
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发表时间：
2002-05-15
影响因子：
5.3
通讯作者：
Bottjer, SW
中科院分区：
文献类型：
--
作者：
DeWulf, V;Bottjer, SW
与斑胸草雀的歌曲学习相关的大脑区域更大，雄性比雌性包含更多的神经元。细胞增殖，迁移，生存和规格的差异可能都有助于不同的发展中的鸟类鸣唱控制系统。本研究量化了幼年和成年鸟类端脑脑室区（VZ）内的细胞增殖水平，以寻找可能有助于构建歌曲控制回路的有丝分裂活动的年龄和性别差异。对两种性别的青少年和成年人给予[H-3]胸苷单次脉冲，2小时后处死动物。在X区、前连合和高音中心（HVC）水平对端脑VZ内的胸苷标记进行分析，发现了两个主要结果：（1）由于VZ内分裂细胞数量的减少，雄性和雌性的有丝分裂活性水平均随年龄的增加而降低，（2）胸苷标记的性别差异发生在限制，VZ的局部区段在青少年的X区和前连合的水平，但不是成年人。因此，总体增殖活性随着鸟类的成熟而降低，并且VZ的所有区域中的细胞分裂的发生率在两种性别中变得相等，使得在成年期没有明显的性二态性增殖区域。这些数据表明，VZ内的性二态增殖区域可能包含产生歌曲控制神经元的前体细胞，因此幼年雄性的有丝分裂活动率较高，可能有助于歌曲控制核团（如HVC和X区）的生长。
Brain regions associated with song learning in zebra finches are larger and contain more neurons in males than females. Differences in cell proliferation, migration, survival, and specification may all contribute to the divergent development of the song-control system in developing birds. This study quantified levels of cell proliferation within the telencephalic ventricular zone (VZ) of juvenile and adult birds to look for both age and sex differences in mitotic activity that might contribute to the construction of song-control circuits. A single pulse of [H-3] thymidine was administered to juveniles and adults of both sexes, and animals were killed 2 hr later. Analysis of thymidine labeling within the telencephalic VZ at the levels of area X, the anterior commissure, and high vocal center (HVC) revealed two major findings: (1) levels of mitotic activity decreased as a function of age in both males and females because of a reduction in the number of dividing cells within the VZ, and (2) sex differences in thymidine labeling occurred in restricted, localized segments of the VZ at the levels of area X and the anterior commissure in juveniles but not adults. Thus, overall proliferative activity decreases as birds mature, and the incidence of cell division in all regions of the VZ becomes equivalent in both sexes, such that no regions of sexually dimorphic proliferation are evident by adulthood. These data suggest that regions of sexually dimorphic proliferation within the VZ may contain precursor cells that give rise to song-control neurons, such that higher rates of mitotic activity in juvenile males could contribute to the growth of song-control nuclei such as HVC and area X.