Koussa Mounir A, Tolbert Leslie P, Oland Lynne A
Department of Neuroscience, University of Arizona, Tucson, AZ 85721, USA.
Neuron Glia Biol. 2010 Nov;6(4):245-61. doi: 10.1017/S1740925X11000081. Epub 2011 Sep 21.
In adult olfactory nerves of mammals and moths, a network of glial cells ensheathes small bundles of olfactory receptor axons. In the developing antennal nerve (AN) of the moth Manduca sexta, the axons of olfactory receptor neurons (ORNs) migrate from the olfactory sensory epithelium toward the antennal lobe. Here we explore developmental interactions between ORN axons and AN glial cells. During early stages in AN glial-cell migration, glial cells are highly dye coupled, dividing glia are readily found in the nerve and AN glial cells label strongly for glutamine synthetase. By the end of this period, dye-coupling is rare, glial proliferation has ceased, glutamine synthetase labeling is absent, and glial processes have begun to extend to enwrap bundles of axons, a process that continues throughout the remainder of metamorphic development. Whole-cell and perforated-patch recordings in vivo from AN glia at different stages of network formation revealed two potassium currents and an R-like calcium current. Chronic in vivo exposure to the R-type channel blocker SNX-482 halted or greatly reduced AN glial migration. Chronically blocking spontaneous Na-dependent activity by injection of tetrodotoxin reduced the glial calcium current implicating an activity-dependent interaction between ORNs and glial cells in the development of glial calcium currents.
在哺乳动物和蛾类的成年嗅觉神经中，神经胶质细胞网络包裹着小束的嗅觉受体轴突。在烟草天蛾发育中的触角神经（AN）中，嗅觉受体神经元（ORN）的轴突从嗅觉感觉上皮向触角叶迁移。在这里，我们探讨ORN轴突与AN神经胶质细胞之间的发育相互作用。在AN神经胶质细胞迁移的早期阶段，神经胶质细胞高度染料偶联，在神经中很容易发现正在分裂的神经胶质细胞，并且AN神经胶质细胞对谷氨酰胺合成酶有强烈标记。在这个阶段结束时，染料偶联很少见，神经胶质细胞增殖停止，谷氨酰胺合成酶标记消失，并且神经胶质细胞的突起开始延伸以包裹轴突束，这一过程在变态发育的其余阶段持续进行。在网络形成的不同阶段对活体AN神经胶质细胞进行全细胞和穿孔膜片钳记录，发现了两种钾电流和一种R样钙电流。长期在体内暴露于R型通道阻滞剂SNX-482会阻止或大大减少AN神经胶质细胞的迁移。通过注射河豚毒素长期阻断自发的钠依赖性活动，会降低神经胶质细胞的钙电流，这表明在神经胶质细胞钙电流的发育中，ORN与神经胶质细胞之间存在活动依赖性相互作用。
