Spatial heterogeneity of intracellular Ca2+ signals in axons of basket cells from rat cerebellar slices
Spatial heterogeneity of intracellular Ca2+ signals in axons of basket cells from rat cerebellar slices
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DOI：
10.1111/j.1469-7793.1997.509bj.x
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发表时间：
1997-08-01
影响因子：
5.5
通讯作者：
Caputo, C
中科院分区：
文献类型：
--
作者：
Llano, I;Tan, YSP;Caputo, C
1.采用全细胞记录技术和数字荧光成像技术，研究了小脑篮状细胞内钙离子（Ca（i）（2+））动态变化，该细胞的树突、轴突和突触前末梢共面，是同时进行所有功能域光学测量的最佳配置.在Cs+负载的神经元中，去极化脉冲在单个轴突静脉曲张和突触终末中诱导了大的Ca ~（2+）瞬变，而在静脉曲张之间或体-树突结构域中的信号要弱得多.轴索分支点一致地显示[Ca 2 +]（i）与轴索终末和静脉曲张中的[Ca 2 +]（i）类似的幅度和时间过程。在充满生物细胞素的篮状细胞中，静脉曲张样血管沿着轴突包括其分支点存在。因此，轴突扩大不是由于荧光诱导的细胞损伤。在去极化列车后，在KF负载的细胞中也观察到Ca-1（2+）信号的空间异质性，表明这种行为是篮状细胞中Ca-1（2+）稳态的内在特性。我们的结论是，篮状细胞轴突的去极化引起突触终末、过渡静脉曲张和分支点的局部高Ca ~（2+）信号。虽然突触前结构中的高[Ca 2 +]（i）可能触发递质释放，但分支点处的Ca-1（2+）瞬变可能控制轴突树枝化中的信号传输。
1. Using tight-seal whole-cell recording and digital fluorescence imaging, we studied intracellular calcium (ca(i)(2+)) dynamics in cerebellar basket cells, whose dendrites, axon and presynaptic terminals are coplanar, an optimal configuration for simultaneous optical measurements of all functional domains.2. In Cs+-loaded neurones, depolarizing pulses induced large Ca-i(2+) transients in single axonal varicosities and synaptic terminals, contrasting with much weaker signals between varicosities or in the somato-dendritic domain.3. Axonal branch points consistently displayed [Ca2+](i) rises of similar magnitude and time course to those in axonal terminals and varicosities.4. In biocytin-filled basket cells, varicosity-like swellings were present along the axon including its branch points. Thus, axonal enlargements are not due to fluorescence-induced cell damage.5. The spatial heterogeneity of Ca-i(2+) signals was also observed in Kf-loaded cells upon depolarizing trains, suggesting that this behaviour is an intrinsic property of Ca-i(2+) homeostasis in basket cells.6. We conclude that depolarization of basket cell axons evokes high local Ca-i(2+) signals in synaptic terminals, en passant varicosities and branch points. While high [Ca2+](i) in presynaptic structures presumably triggers transmitter release, Ca-i(2+) transients at branch points may control signal transmission in the axonal arborization.