Multi-glomerular projection of single olfactory receptor neurons is conserved among amphibians.
Multi-glomerular projection of single olfactory receptor neurons is conserved among amphibians.
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单个嗅觉受体神经元的多肾小球投射在两栖动物中是保守的。
DOI：
10.1002/cne.24887
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Manzini,Ivan
中科院分区：
文献类型：
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作者：
Weiss,Lukas;Jungblut,LucasD;Pozzi,AndreaG;Zielinski,BarbaraS;O'Connell,LaurenA;Hassenklöver,Thomas;Manzini,Ivan
外周嗅觉器官中的单个受体神经元将长轴突延伸到嗅球中，与称为肾小球的球形神经元区域中的投射神经元形成突触。一般来说，所有脊椎动物的气味图形成和气味处理都是基于这样的假设，即受体神经元轴突专门连接到单个肾小球，而没有任何轴突分支。我们比较测试了这一假设在多个鱼类和两栖类物种（两性）通过应用稀疏细胞电穿孔跟踪单个嗅觉受体神经元轴突。海七鳃鳗（无颌鱼）和斑马鱼（硬骨鱼）支持无分支轴突的概念，94%的轴突终止于单个肾小球。相比之下，轴突预测的蝾螈（蝾螈）分支广泛之前，进入六个不同的肾小球。受体神经元轴突标记的青蛙物种（Pipidae，蟾蜍，雨蛙，和Dendrobatidae）主要分叉前进入肾小球和59和50%连接到多个肾小球在幼虫和postmetamorphotic动物，分别。独立的发育阶段，生活方式和适应特定的栖息地，它似乎是一个共同的特点，两栖类嗅觉受体神经元轴突经常分叉和连接到多个肾小球。我们的研究挑战的unbranched轴突的概念，作为一个普遍的脊椎动物的功能，可以想象，后来分歧的脊椎动物偏离it.We提出，这种不寻常的布线逻辑周围的分歧的陆生四足动物谱系从其水生祖先的进化，并可能是一种替代方式的气味处理的基础。
Individual receptor neurons in the peripheral olfactory organ extend long axons into the olfactory bulb forming synapses with projection neurons in spherical neuropil regions, called glomeruli. Generally, odor map formation and odor processing in all vertebrates is based on the assumption that receptor neuron axons exclusively connect to a single glomerulus without any axonal branching. We comparatively tested this hypothesis in multiple fish and amphibian species (both sexes) by applying sparse cell electroporation to trace single olfactory receptor neuron axons. Sea lamprey (jawless fish) and zebrafish (bony fish) support the unbranched axon concept, with 94% of axons terminating in single glomeruli. Contrastingly, axonal projections of the axolotl (salamander) branch extensively before entering up to six distinct glomeruli. Receptor neuron axons labeled in frog species (Pipidae, Bufonidae, Hylidae, and Dendrobatidae) predominantly bifurcate before entering a glomerulus and 59 and 50% connect to multiple glomeruli in larval and postmetamorphotic animals, respectively. Independent of developmental stage, lifestyle, and adaptations to specific habitats, it seems to be a common feature of amphibian olfactory receptor neuron axons to frequently bifurcate and connect to multiple glomeruli. Our study challenges the unbranched axon concept as a universal vertebrate feature and it is conceivable that also later diverging vertebrates deviate from it. We propose that this unusual wiring logic evolved around the divergence of the terrestrial tetrapod lineage from its aquatic ancestors and could be the basis of an alternative way of odor processing.