Calcium signaling components of oscillating invertebrate neurons in vitro.
Calcium signaling components of oscillating invertebrate neurons in vitro.
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体外振荡无脊椎动物神经元的钙信号成分。
DOI：
10.1016/s0306-4522(02)00973-9
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发表时间：
2003
期刊：
影响因子：
3.3
通讯作者：
Selverston,AI
中科院分区：
文献类型：
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作者：
Levi,R;Samoilova,M;Selverston,AI
我们研究了龙虾口胃神经节爆发-尖峰神经元的Ca ~（2+）动力学。神经节中的神经元在原位经历膜电压的自发振荡，周期为1-10 s。我们发现，从神经节分离的神经元，充满荧光钙指示剂Fluo-4显示膜电位和胞浆Ca 2+浓度（[Ca 2 +]I）的同时变化。这些Ca 2+信号在振幅和时间常数方面都是高度异质的。它们表现出可变的空间分布，索马表现出低和慢信号，以及大和快信号的过程中的区域。该过程中的Ca 2+瞬变依赖于外部Ca 2+，可以被Co2+阻断，但不能被其他更特异的Ca 2+电流阻断剂阻断。相反，硝苯地平是一种已知的Ca 2+电流阻断剂，影响Ca 2+信号的分布，这表明Ca 2+通道的特异性定位。虽然信号并不完全依赖于动作电位，但当动作电位被河豚毒素阻断时，信号大大降低。信号的终止仅轻微地依赖于Ca 2+缓冲机制，例如线粒体、Ca 2 +/Na+和Ca 2 +/H+交换器。我们还证明了咖啡因敏感的内部存储在口胃神经节细胞的存在。存储分布是不同的，但与电压相关的分布重叠。咖啡因激活的Ca ~（2+）信号在索马胞体中最大，在突起中较小。与电压激活的Ca 2+信号不同，该信号不被Co2+阻断。尽管如此，这两种类型的信号在咖啡因应用期间会相互作用。这种独特的空间分离的两个Ca 2+源可能具有重要的功能意义。
We have studied the Ca2+dynamics of bursting–spiking neurons in the lobster stomatogastric ganglion. Neurons in this ganglion undergo spontaneous oscillations in membrane voltage with a period of 1–10 s in situ. We found that neurons isolated from the ganglion and filled with the fluorescent calcium indicator Fluo-4 show simultaneous changes of membrane potential and cytoplasmic Ca2+concentration ([Ca2+]I). These Ca2+signals are highly heterogeneous both in terms of amplitude and time constants. They showed variable spatial distributions with the soma exhibiting low and slow signals, and a region in the process with large and fast signals. Ca2+transients in the processes are dependent on external Ca2+and can be blocked by Co2+, but not other, more specific Ca2+current blockers. Rather, nifedipine a known Ca2+current blocker, affects the distribution of the Ca2+signal, which suggests a specific localization of Ca2+channels. Although the signal is not absolutely dependent on action potentials, it is greatly reduced when action potentials are blocked by tetrodotoxin. Termination of the signal depends only slightly on Ca2+buffering mechanisms such as mitochondria, Ca2+/Na+and Ca2+/H+exchangers. We also demonstrate the presence of caffeine-sensitive internal stores in stomatogastric ganglion cells. The store distribution is different but overlaps with the voltage-dependent distribution. The maximal caffeine-activated Ca2+signal is in the soma and it is smaller in the processes. Unlike the voltage-activated Ca2+signal this signal is not blocked by Co2+. Nevertheless, the two types of signal interact during caffeine application. This unique spatial separation of two Ca2+sources may have important functional implication.