Lohr C, Oland L A, Tolbert L P
ARL Division of Neurobiology, University of Arizona, Tucson, Arizona, USA.
Glia. 2001 Dec;36(3):309-20. doi: 10.1002/glia.1118.
In the olfactory (antennal) lobe of the moth Manduca sexta, olfactory receptor axons strongly influence the distribution and morphology of glial cells. In the present study, we asked whether the development of the electrophysiological properties of the glial cells is influenced by the receptor axons. Whole-cell currents were measured in antennal lobe glial cells in acute brain slices prepared from animals at different stages of metamorphic development (stages 3, 6, and 12). Outward currents were induced by depolarizing voltage steps from a holding potential of -70 mV. At all developmental stages investigated, the outward currents were partly blocked by bath application of the potassium channel blocker 4-aminopyridine (4AP, 10 mM) or by including tetraethylammonium (TEA, 30 mM) in the pipette solution. The relative contribution of the 4AP-sensitive current to the outward current increased from 18% at stages 3 and 6 to 42% at stage 12, while the TEA-sensitive current increased from 18% at stage 3 to 81% at stage 6, and then declined again to 40% at stage 12. In contrast, in the absence of receptor axons, these changes in the contribution of the TEA- and 4AP-sensitive currents to the total outward current did not occur; rather, the current profile remained in the most immature state (stage 3). The results suggest that olfactory receptor axons are essential for development of the mature pattern of glial potassium currents.
在烟草天蛾的嗅觉(触角)叶中,嗅觉受体轴突强烈影响神经胶质细胞的分布和形态。在本研究中,我们探究了神经胶质细胞电生理特性的发育是否受受体轴突的影响。在由处于变态发育不同阶段(3期、6期和12期)的动物制备的急性脑片中,测量触角叶神经胶质细胞的全细胞电流。通过从 -70 mV的钳制电位进行去极化电压阶跃来诱导外向电流。在所有研究的发育阶段,外向电流部分被浴加钾通道阻滞剂4-氨基吡啶(4AP,10 mM)阻断,或通过在移液管溶液中加入四乙铵(TEA,30 mM)来阻断。4AP敏感电流对外向电流的相对贡献从3期和6期的18%增加到12期的42%,而TEA敏感电流从3期的18%增加到6期的81%,然后在12期再次下降到40%。相反,在没有受体轴突的情况下,TEA和4AP敏感电流对总外向电流贡献的这些变化并未发生;相反,电流分布保持在最不成熟的状态(3期)。结果表明,嗅觉受体轴突对于神经胶质钾电流成熟模式的发育至关重要。