Action potential modulates Ca2+-dependent and Ca2+-independent secretion in a sensory neuron.
Action potential modulates Ca2+-dependent and Ca2+-independent secretion in a sensory neuron.
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DOI：
10.1016/j.bpj.2008.11.037
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发表时间：
2009-03
影响因子：
3.4
通讯作者：
Hui Zheng;Juan Fan;W. Xiong;Chen Zhang;Xiao‐bing Wang;Tao Liu;Hong-ju Liu;Lei Sun;Yeshi Wang;Lianghong Zheng;Bai-ren Wang;C. Zhang;Zhuan Zhou
中科院分区：
文献类型：
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作者：
Hui Zheng;Juan Fan;W. Xiong;Chen Zhang;Xiao‐bing Wang;Tao Liu;Hong-ju Liu;Lei Sun;Yeshi Wang;Lianghong Zheng;Bai-ren Wang;C. Zhang;Zhuan Zhou
神经递质的释放通常需要钙触发。然而，背根神经节（DRG）神经元胞体除了具有经典的钙依赖性分泌（CDS）外，还具有钙非依赖性但电压依赖性分泌（CIVDS）。本文研究了CIVDS的生理作用以及动作电位（AP）在DRG索马体中诱导的CIVDS和CDS的作用。利用膜电容测量，笼状钙光解，和膜电容动力学分析，我们证明了AP诱导的分泌CIVDS和CDS组件。生理刺激后，AP诱导分泌的主要成分是CIVDS（自发放电）或CDS（高强度刺激）。AP频率调节CDS偶联的胞吐作用和CIVDS偶联的胞吞作用，但不调节CIVDS偶联的胞吐作用和CDS偶联的胞吞作用。最后，CIVDS没有贡献的兴奋性突触后电流诱导的AP在DRG突触前末梢在脊髓。因此，CIVDS可能是AP诱导的索马体分泌的重要生理成分。这些发现为DRG神经元的初级感觉过程带来了新的见解。
Neurotransmitter release normally requires calcium triggering. However, the somata of dorsal root ganglion (DRG) neurons possess a calcium-independent but voltage-dependent secretion (CIVDS) in addition to the classic calcium-dependent secretion (CDS). Here, we investigated the physiological role of CIVDS and the contributions of CIVDS and CDS induced by action potentials (APs) in DRG soma. Using membrane capacitance measurements, caged calcium photolysis, and membrane capacitance kinetics analysis, we demonstrated that AP-induced secretion had both CIVDS and CDS components. Following physiological stimuli, the dominant component of AP-induced secretion was either CIVDS for spontaneous firing or CDS for high-intensity stimuli. AP frequency modulates CDS-coupled exocytosis and CIVDS-coupled endocytosis but not CIVDS-coupled exocytosis and CDS-coupled endocytosis. Finally, CIVDS did not contribute to excitatory postsynaptic currents induced by APs in DRG presynaptic terminals in the spinal cord. Thus, CIVDS is probably an essential physiological component of AP-induced secretion in the soma. These findings bring novel insights into primary sensory processes in DRG neurons.