EFFECTS OF UNILATERAL COCHLEA REMOVAL ON ANTEROVENTRAL COCHLEAR NUCLEUS NEURONS IN DEVELOPING GERBILS
EFFECTS OF UNILATERAL COCHLEA REMOVAL ON ANTEROVENTRAL COCHLEAR NUCLEUS NEURONS IN DEVELOPING GERBILS
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DOI：
10.1002/cne.902830402
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发表时间：
1989-05-22
影响因子：
2.5
通讯作者：
RUBEL, EW
中科院分区：
文献类型：
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作者：
HASHISAKI, GT;RUBEL, EW
在光学显微镜下研究了耳蜗核神经元的传入调节随年龄的变化。对3个年龄组蒙古沙鼠进行单侧耳蜗摘除术；产后1、8和20周。动物存活了2天或2周。另一组新生手术动物的存活时间延长了9周。计数耳蜗前腹侧核（AVCN）神经元数量，并测量AVCN大球形细胞的横截面积。在手术时1周大的动物中，2天后AVCN上的神经元数量减少35%，2周后减少58%，内耳破坏后9周减少59%。然而，在手术时20周龄的动物中，手术后2天或2周AVCN均未出现细胞损失。各年龄组动物耳蜗消融后AVCN大球形细胞横截面积减少。在第8周和第20周摘除耳蜗的沙鼠平均下降14-18%。这种效果早在耳蜗切除后2天就可见。第1周切除耳蜗的动物变化最大；2天下降25%，摘除耳蜗2周后下降38%。新生儿耳蜗摘除后9周未见明显的进一步变化。结果表明，1周龄沙鼠耳蜗核神经元对外周丢失的易感性高于老年沙鼠。在所有组中，耳蜗消融后细胞大小和神经元数量的变化比以前报道的要快得多。有趣的是，这些变化发生在听力出现之前，也发生在可测量的耳蜗麦克风对声音的反应出现之前。
Afferent regulation of neurons in the cochlear nucleus as a function of age was investigated at the light microscope level. Unilateral cochlea removal was performed on Mongolian gerbils of three age groups; 1, 8 and 20 weeks postnatal. Animals survived for either 2 days or 2 weeks. An additional group of neonatally operated animals had a prolonged survival of 9 weeks. The number of neurons in anteroventral cochlear nucleus (AVCN) was counted, and crosssectional area measurements of large spherical cells in AVCN were made. In animals 1 week old at the time of surgery, there was a 35% reduction in neuron number on AVCN after 2 days, a 58% reduction after 2 weeks, and a 59% reduction 9 weeks after inner ear destruction. However, in animals 20 weeks old at the time of surgery, there was no cell loss in AVCN either 2 days or 2 weeks after surgery. Animals in each age group showed a reduction in cross-sectional area of large spherical cells in AVCN after cochlea ablation. The gerbils that underwent cochlea removal at 8 and 20 weeks showed an average decrease of 14-18%. This effect was seen as early as 2 days after cochlea removal. Animals that underwent cochlea removal at 1 week exhibited the greatest change; a 25% decrease at 2 days progressed to 38% a 2 weeks following cochlea removal. No appreciable further changes were seen at 9 weeks after neonatal cochlea removal. The results indicate greater susceptibility of 1-week-old gerbil cochlear nucleus neurons to peripheral loss than found in older animals. In all groups the changes in cell size and neuron number occurred considerably sooner after cochlea ablation than previously has been reported. Interestingly, these changes were seen before the onset of hearing and before the onset of measurable cochlear microphonic responses to sound.