Laboratory of Neuronal Plasticity and Neurorepair, Institute for Neuroscience of Castile & Leon (INCyL), Universidad de Salamanca, Salamanca, Spain.
Institute of Biomedical Research of Salamanca, IBSAL, Salamanca, Spain.
Sci Rep. 2017 Jul 18;7(1):5654. doi: 10.1038/s41598-017-05970-1.
The olfactory bulb (OB) neurons establish a complex network that ensures the correct processing of the olfactory inputs. Moreover, the OB presents a lifelong addition of new neurons into its existing circuitry. This neurogenesis is considered essential for the OB function. However, its functional impact on physiology and behavior is still unclear. Here, we investigate the mechanisms of OB plasticity that underlie bulbar physiology in relation to severe damage of neurogenesis. The neurogenesis of young mice was altered by ionizing radiation. Afterwards, both multi-channel olfactometry and electrophysiological studies were performed. Furthermore, neurogenesis and differentiation of the newly formed cells were assessed using bromodeoxyuridine labeling combined with a wide battery of neuronal markers. Our results demonstrate a reduction in both neurogenesis and volume of the OB in irradiated animals. The number of neuroblasts reaching the OB was reduced and their differentiation rate into interneurons selectively changed; some populations were noticeably affected whereas others remained preserved. Surprisingly, both olfactory detection and discrimination as well as electrophysiology presented almost no alterations in irradiated mice. Our findings suggest that after damaging postnatal neurogenesis, the neurochemical fate of some interneurons changes within a new biological scenario, while maintaining homeostasis and olfaction.
嗅球（OB）神经元建立了一个复杂的网络，确保了嗅觉输入的正确处理。此外，OB 存在着将新神经元终生添加到其现有电路中的现象。这种神经发生被认为对 OB 功能至关重要。然而，其对生理学和行为的功能影响仍不清楚。在这里，我们研究了 OB 可塑性的机制，这些机制与严重破坏神经发生有关。通过电离辐射改变年轻小鼠的神经发生，然后进行多通道嗅觉测量和电生理研究。此外，使用溴脱氧尿苷标记结合广泛的神经元标记物来评估新形成细胞的神经发生和分化。我们的结果表明，照射动物的神经发生和 OB 体积均减少。到达 OB 的神经母细胞数量减少，其向中间神经元分化的速度选择性改变；一些群体明显受到影响，而其他群体则保持不变。令人惊讶的是，在照射的小鼠中，嗅觉检测和辨别以及电生理学几乎没有变化。我们的发现表明，在破坏产后神经发生后，一些中间神经元的神经化学命运在新的生物学环境中发生变化，同时保持内稳态和嗅觉。
