Division of Brain Function, National Institute of Genetics, Yata, Mishima, Shizuoka, Japan.
Dev Neurobiol. 2012 Dec;72(12):1559-76. doi: 10.1002/dneu.22030. Epub 2012 Jul 20.
The guidepost neurons for the lateral olfactory tract, which are called lot cells, are the earliest-generated neurons in the neocortex. They migrate tangentially and ventrally further down this tract, and provide scaffolding for the olfactory bulb axons projecting into this pathway. The molecular profiles of the lot cells are largely uncharacterized. We found that lot cells specifically express metabotropic glutamate receptor subtype-1 at a very early stage of development. This receptor is functionally competent and responds to a metabotropic glutamate receptor agonist with a transient increase in the intracellular calcium ion concentration. When the glutamatergic olfactory bulb axons were electrically stimulated, lot cells responded to the stimulation with a calcium increase mainly via ionotropic glutamate receptors, suggesting potential neurotransmission between the axons and lot cells during early development. Together with the finding that lot cells themselves are glutamatergic excitatory neurons, our results provide another notable example of precocious interactions between the projecting axons and their intermediate targets.
外侧嗅束的引导神经元，称为 LOT 细胞，是新皮层中最早产生的神经元。它们沿着这个束状结构进行切线和腹侧迁移，并为投射到这个途径的嗅球轴突提供支架。LOT 细胞的分子特征在很大程度上还没有被描述。我们发现 LOT 细胞在发育的早期阶段特异性表达代谢型谷氨酸受体亚型 1。这种受体具有功能性，并对代谢型谷氨酸受体激动剂做出反应，导致细胞内钙离子浓度短暂增加。当电刺激谷氨酸能嗅球轴突时，LOT 细胞主要通过离子型谷氨酸受体对刺激做出钙增加反应，提示在早期发育过程中，轴突和 LOT 细胞之间可能存在潜在的神经传递。结合 LOT 细胞本身是谷氨酸能兴奋性神经元的发现，我们的结果提供了另一个投射轴突与其中间靶标之间早熟相互作用的显著例子。
