Characterization of voltage-dependent Ca2+ currents in identified Drosophila motoneurons in situ.
Characterization of voltage-dependent Ca2+ currents in identified Drosophila motoneurons in situ.
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果蝇原位运动神经元中电压依赖性 Ca2+ 电流的表征。
DOI：
10.1152/jn.90464.2008
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发表时间：
2008
影响因子：
2.5
通讯作者：
Levine,RichardB
中科院分区：
文献类型：
--
作者：
Worrell,JasonW;Levine,RichardB
电压依赖性Ca2+通道有助于神经递质释放，突触信息的整合和神经元内的基因调控。因此，了解不同Ca2+通道表达的位置是了解网络内神经元功能的重要一步。果蝇为探索完整系统中电压依赖性Ca2+通道的功能提供了一个有用的模型，但原位果蝇动脉瘤中央过程中的Ca2+电流尚未得到很好的描述。本研究的目的是表征电压依赖性Ca2+电流原位鉴定的幼虫运动神经元。从鉴定的运动神经元的体细胞全细胞记录显示细胞外Ca2+对spike形状和放电速率的显著影响。使用全细胞电压钳，以及Na+和K+通道阻滞剂，Ca2+依赖的内向电流被隔离。果蝇基因组包含三个与脊椎动物电压依赖性Ca2+通道同源的基因：Dmca1A、Dmca1D和dmα 1g。我们使用dmca1a和dmca1das的突变体以及RNAi转基因dmca1d的靶向表达来确定负责从两个已鉴定的运动神经元记录的电压依赖性Ca2+电流的基因。我们的研究结果表明，dmca1a是运动神经元体树突过程中记录的电压依赖性Ca2+电流的主要贡献者，而dmca1a以前被定位于突触前末端，在那里它是神经递质释放所必需的。dmca1amutants和dmca1amutants的细胞中放电特性的改变表明这两个基因在形成放电特性中都起作用。
Voltage-dependent Ca2+channels contribute to neurotransmitter release, integration of synaptic information, and gene regulation within neurons. Thus understanding where diverse Ca2+channels are expressed is an important step toward understanding neuronal function within a network.Drosophilaprovides a useful model for exploring the function of voltage-dependent Ca2+channels in an intact system, but Ca2+currents within the central processes ofDrosophilaneurons in situ have not been well described. The aim of this study was to characterize voltage-dependent Ca2+currents in situ from identified larval motoneurons. Whole cell recordings from the somata of identified motoneurons revealed a significant influence of extracellular Ca2+on spike shape and firing rate. Using whole cell voltage clamp, along with blockers of Na+and K+channels, a Ca2+-dependent inward current was isolated. TheDrosophilagenome contains three genes with homology to vertebrate voltage-dependent Ca2+channels:Dmca1A, Dmca1D,andDmα1G.We used mutants ofDmca1AandDmca1Das well as targeted expression of an RNAi transgene toDmca1Dto determine the genes responsible for the voltage-dependent Ca2+current recorded from two identified motoneurons. Our results implicateDmca1Das the major contributor to the voltage-dependent Ca2+current recorded from the somatodendritic processes of motoneurons, whereasDmca1Ahas previously been localized to the presynaptic terminal where it is essential for neurotransmitter release. Altered firing properties in cells from bothDmca1DandDmca1Amutants indicate a role for both genes in shaping firing properties.