Functional properties and axon terminations of interneurons in laminae III-V of the mammalian spinal dorsal horn in vitro.
Functional properties and axon terminations of interneurons in laminae III-V of the mammalian spinal dorsal horn in vitro.
复制标题
体外哺乳动物脊髓背角 III-V 层中间神经元的功能特性和轴突终止。
DOI：
10.1152/jn.1992.68.5.1746
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发表时间：
1992
影响因子：
2.5
通讯作者：
Schneider,SP
中科院分区：
文献类型：
--
作者：
Schneider,SP
1.在离体制备的仓鼠背角与感觉神经支配的离体皮肤贴片中，研究了脊髓第III-V层中间神经元的功能组织。40个神经元的形态学细节可视化细胞内注射辣根过氧化物酶。主动和被动膜特性，突触反应皮肤神经齐射，并确定25个细胞与确定的轴突对无害的机械刺激的反应。2.神经元分为两类：1）具有局部轴突的细胞，在细胞索马和树突附近分支，产生许多突触终扣（740 +/-504/轴突;平均值+/- SD），通常排列成簇，2）具有深轴突的神经元，通常分叉成喙侧和尾侧子分支，长达2.5 mm，在细胞体和树突的腹侧发出侧支，并且形成比局部轴突细胞显著更少的终扣（155 +/-140/轴突）。局部轴突和深层轴突细胞的绝大多数终扣为传递型，分别占89%和83%。3.局部轴突细胞的树突树在背腹侧（119 +/- 42微米）和内侧（128 +/- 45微米）相对紧凑，但在吻尾侧（404 +/- 121微米）伸长。相比之下，深层轴突细胞的树突树在背腹侧（218 +/- 88微米）和内侧（180 +/- 34微米）辐射明显更远，但表现出相当的吻尾扩散（413 +/- 128微米）。有背腹侧和中间外侧树突蔓延和中间外侧索马的位置为任一细胞类型之间没有相关性。然而，对于位于内侧的深层轴突细胞的rostrocaudal树突状细胞的蔓延高达180%以上，比那些位于侧面。对于近一半的所有细胞（49%; 17/35）树突状突起延伸到板II背侧。4.局部轴突细胞的静息膜电位比深层轴突细胞的静息膜电位更负（分别为-59.5 +/- 6.1和-53.6 +/- 4.7 mV），但两种类型产生的动作电位的幅度和持续时间相似。神经元输入电阻（RN）和膜时间常数（τ m）在细胞与细胞之间变化很大，但对于局部轴突（77.4 +/- 46.8 M Ω，13.4 +/- 9.5 ms）和深层轴突细胞（46.5 +/- 19.2 M Ω，6.6 +/- 3.0 ms）没有显著差异。5.在有髓传入纤维的Volleys激活快速上升的兴奋性突触后电位（EPSP），表现出较晚，更慢的上升电位与多个组件在大多数深轴突（89%）和局部轴突（72%）神经元。（400字处截断摘要）
1. The functional organization of interneurons in spinal laminae III-V was studied in an isolated preparation of hamster dorsal horn with sensory innervation from an excised skin patch. Morphological details of 40 neurons were visualized by intracellular injection of horseradish peroxidase. Active and passive membrane properties, synaptic responses to cutaneous nerve volleys, and responses to innocuous mechanical stimuli were determined for 25 cells with identified axons. 2. Neurons were classified into two types: 1) cells with local axons, branching in proximity to the cell soma and dendrites, that produced numerous synaptic boutons (740 +/- 504/axon; mean +/- SD), often arranged in clusters and 2) neurons with deep axons that usually bifurcated into rostral and caudal daughter branches up to 2.5 mm long, giving off collaterals ventral to the cell body and dendrites and forming significantly fewer boutons (155 +/- 140/axon) than local axon cells. A majority of boutons of local axon and deep axon cells, 89 and 83%, respectively, were of the en passant type. 3. Dendritic trees of local axon cells were relatively compact dorsoventrally (119 +/- 42 microns) and mediolaterally (128 +/- 45 microns), but were elongated rostrocaudally (404 +/- 121 microns). In comparison, dendritic trees of deep axon cells radiated significantly farther dorsoventrally (218 +/- 88 microns) and mediolaterally (180 +/- 34 microns), but exhibited comparable rostrocaudal spread (413 +/- 128 microns). There was no correlation between dorsoventral and mediolateral dendritic spread and mediolateral soma location for either cell type. However, for medially situated deep axon cells the rostrocaudal dendritic spread was up to 180% greater than for those located laterally. For nearly one-half of all cells (49%; 17/35) dendritic processes extended dorsally into lamina II. 4. Local axon cells had resting membrane potentials that were more negative than deep axon cells (-59.5 +/- 6.1 and -53.6 +/- 4.7 mV, respectively), but the amplitude and duration of action potentials generated by the two types were similar. Neuronal input resistance (RN) and membrane time constant (tau m) varied widely from cell to cell, but were not significantly different for local axon (77.4 +/- 46.8 M omega, 13.4 +/- 9.5 ms) and deep axon cells (46.5 +/- 19.2 M omega, 6.6 +/- 3.0 ms). 5. Volleys in myelinated afferent fibers activated fast rising excitatory postsynaptic potentials (EPSPs) that exhibited later, more slowly rising potentials with multiple components in a majority of deep axon (89%) and local axon (72%) neurons.(ABSTRACT TRUNCATED AT 400 WORDS)