Regional distribution of calcium elevation during sensory transduction in spider mechanoreceptor neurons
Regional distribution of calcium elevation during sensory transduction in spider mechanoreceptor neurons
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DOI：
10.1016/j.neures.2008.09.006
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发表时间：
2008-12-01
影响因子：
2.9
通讯作者：
French, Andrew S.
中科院分区：
文献类型：
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作者：
Hoeger, Ulli;Meisner, Shannon;French, Andrew S.
蜘蛛机械感觉 VS-3 神经元接受外周传出突触调节，传出突触和递质受体类型存在区域差异。 VS-3体细胞具有电压激活的钙电流，但其他区域钙变化的水平和时间进程尚不清楚。钙在这些神经元中的作用尚不完全清楚，但可能包括机械敏感性和反应动力学的调节。在这里，我们使用俄勒冈绿 BAPTA-1 荧光测量了 VS-3 感觉树突、胞体和轴突中由单一机械诱导动作电位引起的钙浓度升高。每次动作电位后，钙浓度升高约 1 nM。三个区域中钙上升和下降的时间进程相似，但感觉树突中的上升幅度比体细胞中高出约 50%。 T 型钙通道 Ca(V)3.1(alpha(1g)) 同种型抗体标记了所有三个神经元区域。一些 Ca(V)3.1 标记与突触蛋白标记共定位，表明钙通道在传出调节中发挥一定作用。我们得出的结论是，机械刺激的动作电位在感觉树突尖端附近开始，并快速通过神经元到达轴突，激活所有三个区域中的低电压激活的钙通道，并导致每个区域中的钙浓度迅速升高。这些结果表明钙在机械感觉的几个阶段中发挥重要作用。 (C) 2008 Elsevier Ireland Ltd 和日本神经科学学会。版权所有。
Spider mechanosensory VS-3 neurons receive peripheral efferent synaptic modulation, with regional variations in the types of efferent synapses and transmitter receptors. VS-3 somata possess a voltage-activated calcium current, but the levels and time courses of calcium changes in other regions are unknown. The roles of calcium in these neurons are not completely understood, but could include modulation of both mechanosensitivity and response dynamics. Here, we measured calcium concentration rises caused by single, mechanically induced action potentials in VS-3 sensory dendrites, somata and axons, using Oregon Green BAPTA-1 fluorescence. Calcium concentration rose by similar to 1 nM following each action potential. Time courses of calcium rise and fall were similar in the three regions but the rise in amplitude was about 50% higher in the sensory dendrite than in the soma. Antibody to the Ca(V)3.1(alpha(1g)) isotype of T-type calcium channel labeled all three neuronal regions. Some Ca(V)3.1 labeling colocalized with synapsin labeling, suggesting that calcium channels play some part in efferent modulation. We conclude that mechanically stimulated action potentials start near sensory dendrite tips and pass rapidly through the neurons to the axons, activating low voltage activated calcium channels in all three regions and causing calcium concentration to rise rapidly in each region. These results suggest important roles for calcium in several stages of mechanosensation. (C) 2008 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.