SUBSTANCE-P ELEVATES INTRACELLULAR CALCIUM IN BOTH NEURONS AND GLIAL-CELLS FROM THE DORSAL HORN OF THE SPINAL-CORD
SUBSTANCE-P ELEVATES INTRACELLULAR CALCIUM IN BOTH NEURONS AND GLIAL-CELLS FROM THE DORSAL HORN OF THE SPINAL-CORD
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DOI：
10.1152/jn.1994.72.3.1192
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发表时间：
1994-09-01
影响因子：
2.5
通讯作者：
MACDERMOTT, AB
中科院分区：
文献类型：
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作者：
HEATH, MJS;WOMACK, MD;MACDERMOTT, AB
1.用微量荧光分光光度法检测急性分离的新生大鼠背角P物质敏感细胞。然后，我们使用形态、生理和免疫细胞化学标准来描绘P物质敏感的背角细胞的两个不同的群体。具有小直径细胞体和许多精细突起的一群细胞通过从内部存储器释放钙来对P物质作出反应。其中许多细胞表达O4表面抗原，因此很可能是胶质细胞，可能来自少突胶质细胞谱系。具有神经胶质属性的细胞中没有一个对N-甲基-D-天冬氨酸(NMDA)有反应，这进一步证明了它们是非神经细胞。在第二组背角细胞中，P物质通过促进钙离子进入而升高[钙](I)。这类细胞在形态上与P物质敏感的胶质细胞不同，因为它表现出大直径的胞体，具有平滑的锥化过程，并且对NMDA敏感。因此，这第二类细胞很可能由神经元组成。与两种细胞中钙升高机制的不同相一致，神经胶质细胞中P物质引起的钙释放动力学与神经元中引起的钙内流反应的动力学有很大的不同。胶质细胞反应的平均上升速率较快(平均=2 6 0+/-10 5 nm/S)，持续时间较短(平均=7 6+/-2 S)，而神经元反应的上升速度较慢(平均=10+/-9 nM/S)，持续时间较长。结论：P物质可直接激活新生大鼠两种不同类型的背角细胞。P物质的作用机制在两类细胞中不同；在神经胶质细胞中，P物质促进内库中的钙离子释放，而在神经元中，P物质促使钙离子从细胞外环境中进入。
1. We used microfluorimetric measurement of [Ca2+](i) to identify substance P-sensitive cells acutely isolated from the dorsal horn of neonatal rats. We then used morphological, physiological, and immunocytochemical criteria to delineate two distinct populations of substance P-sensitive dorsal horn cells.2. One population of cells with small-diameter cell bodies and many fine processes responds to substance P by releasing Ca2+ from internal stores. Many of these cells express the O4 surface antigen, and are thus likely to be glial cells, probably from the oligodendrocyte lineage. None of the cells with glial attributes respond to N-methyl-D-aspartate (NMDA), providing further evidence that they are nonneuronal.3. In a second population of dorsal horn cells, substance P elevates [Ca2+](i) by promoting Ca2+ entry. This class of cells is morphologically distinct from substance P-sensitive glial cells in that it exhibits large-diameter cell bodies, has smooth tapering processes, and is sensitive to NMDA. This second class of cells is therefore likely to consist of neurons.4. Consistent with the identification of different mechanisms of Ca2+ elevation in the two cell types, the kinetics of the substance P-evoked release of Ca2+ in glial cells is very different than the kinetics of the Ca2+ -entry response evoked in neurons. The glial cell response had a rapid average rate of rise (mean = 260 +/- 105 nM/s) and relatively brief duration (mean = 7.6 +/- 2.2 s) whereas the neuronal response had a much slower rate of rise (mean = 10 +/- 9 nM/s) with a much longer duration.5. It is concluded that substance P directly activates two distinct classes of dorsal horn cells in the neonatal rat. The mechanism of action of substance P differs between the two cellular classes; in glial cells, substance P promotes the release of Ca2+ from internal stores, whereas in neurons, substance P causes Ca2+ to enter from the extracellular environment.