Regional calcium regulation within cultured Drosophila neurons:: Effects of altered cAMP metabolism by the learning mutations dunce and rutabaga
Regional calcium regulation within cultured Drosophila neurons:: Effects of altered cAMP metabolism by the learning mutations dunce and rutabaga
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DOI：
10.1523/jneurosci.22-11-04437.2002
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发表时间：
2002-06-01
影响因子：
5.3
通讯作者：
Wu, CF
中科院分区：
文献类型：
--
作者：
Berke, B;Wu, CF
果蝇的dunce（dnc）和rutabaga（rut）突变分别影响cAMP依赖性磷酸二酯酶和Ca 2 + /CaM调节的腺苷酸环化酶。这些突变导致几种学习范式的缺陷，并改变突触传递、生长锥运动和动作电位产生。细胞表型是Ca 2+依赖性的（神经传递和运动性）或介导Ca 2+升高（动作电位产生）。然而，这些缺陷之间的相互关系尚未得到解决。我们已经建立了条件Fura-2成像的钙离子动力学在果蝇的“巨大”神经元培养系统。使用高K+去极化的孤立的神经元，我们观察到一个更大，更快，更动态的反应，从生长锥比细胞体。这种Ca 2+增加依赖于通过Ca 2+通道的内流，并被Na+通道阻断剂TTX抑制。由dnc和rut突变引起的cAMP代谢改变降低了生长锥中的反应幅度，同时延长了索马内的反应。这些较大的细胞的增强的空间分辨率使我们能够分析突变体生长锥的不同结构域内的Ca 2+调节。调制由以前的条件刺激改变的响应幅度和波形的复杂性。此外，车辙破坏了Ca 2+反应的区别与运动丝状伪足的生长锥的周边和中央域之间观察。
The dunce (dnc) and rutabaga (rut) mutations of Drosophila affect a cAMP-dependent phosphodiesterase and a Ca2+ / CaM-regulated adenylyl cyclase, respectively. These mutations cause deficiencies in several learning paradigms and alter synaptic transmission, growth cone motility, and action potential generation. The cellular phenotypes either are Ca2+ dependent (neurotransmission and motility) or mediate a Ca2+ rise (action potential generation). However, interrelations among these defects have not been addressed. We have established conditions for fura-2 imaging of Ca2+ dynamics in the "giant" neuron culture system of Drosophila. Using high K+ depolarization of isolated neurons, we observed a larger, faster, and more dynamic response from the growth cone than the cell body. This Ca2+ increase depended on an influx through Ca2+ channels and was suppressed by the Na+ channel blocker TTX. Altered cAMP metabolism by the dnc and rut mutations reduced response amplitude in the growth cone while prolonging the response within the soma. The enhanced spatial resolution of these larger cells allowed us to analyze Ca2+ regulation within distinct domains of mutant growth cones. Modulation by a previous conditioning stimulus was altered in terms of response amplitude and waveform complexity. Furthermore, rut disrupted the distinction in Ca2+ responses observed between the periphery and central domain of growth cones with motile filopodia.