FUNCTIONAL RELATIONSHIPS BETWEEN NEURONS OF MARGINAL AND SUBSTANTIA GELATINOSA LAYERS OF PRIMATE DORSAL HORN
FUNCTIONAL RELATIONSHIPS BETWEEN NEURONS OF MARGINAL AND SUBSTANTIA GELATINOSA LAYERS OF PRIMATE DORSAL HORN
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DOI：
10.1152/jn.1979.42.6.1590
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发表时间：
1979-01-01
影响因子：
2.5
通讯作者：
RUDA, MA
中科院分区：
文献类型：
--
作者：
PRICE, DD;HAYASHI, H;RUDA, MA
本研究检查了胶质质神经元在将伤害性和非伤害性输入传递到脊髓背角边缘层的脊髓丘脑神经元中的功能作用。在恒河猴中研究了 L[腰]7-S[骶]1 的 I 层（边缘层）和 Rexed 的 II 层（胶质，细分为外部区域 a 和内部区域 b）中的神经元（130 个）。 mulatta]用戊巴比妥钠轻度麻醉。比较了在同一微电极轨道上连续记录的 51 对神经元的反应特性。每对的背侧神经元是第一层脊髓丘脑或非投射神经元，而位于200μm以内的腹侧神经元是第二层神经元。第二层中所有神经元的位置是通过在最大尖峰幅度部位产生的小损伤从组织学上确定的。几类神经元的区别在于它们对施加到其感受野的刺激的反应范围。第二层大多数神经元的特性与先前报道的第一层和背角更深层神经元的特性相似。受到有害机械或热刺激最大程度兴奋的伤害感受特异性神经元对低阈值机械刺激没有反应，主要位于 I 层和 IIa 层。从 51 对神经元获得的数据显示，一对内的神经元经常接收来自相同类型初级传入纤维的汇聚输入。成对的神经元具有重叠的感受野，第二层神经元的感受野比第一层神经元小，第二层神经元的第一尖峰潜伏期比第一层神经元短。一些第二层神经元可能充当兴奋性中间神经元，并将初级传入输入中继到第一层的脊髓丘脑神经元，在那里发生一些额外的收敛。这一结论与高尔基体解剖学研究的观察结果一致。第二层神经元以长潜伏期反应成分对有害热刺激做出反应，这些反应成分在重复刺激下表现出时间总和和长时间放电。中枢促进机制是在第二层神经元中产生的，这些神经元似乎接收来自初级伤害性传入纤维的直接单突触输入。
This study examined the functional role of substantia gelatinosa neurons in the transmission of nociceptive and nonnociceptive input to spinothalamic neurons in the marginal layer of the spinal cord dorsal horn. Neurons (130) in layer I (marginal layer) and Rexed''s layer II (substantia gelatinosa, subdivided into an outer zone, a, and an inner zone, b) of L[lumbar]7-S[sacral]1 were studied in rhesus monkeys [M. mulatta] lightly anesthetized with sodium pentobarbital. The response properties of 51 pairs of neurons recorded successively in the same microelectrode track were compared. The dorsal neuron of each pair was a layer I spinothalamic or non-projection neuron and the ventral neuron, located within 200 .mu.m, was a layer II neuron. The location of all neurons in layer II was determined histologically from small lesions made at the sites of maximum spike amplitudes. Several classes of neurons were distinguished by the range of their responses to stimuli applied to their receptive fields. The properties of most neurons in layer II were similar to those previously reported for neurons in layer I and deeper layers of the dorsal horn. Nociceptive-specific neurons that were maximally excited by noxious mechanical or thermal stimuli did not respond to low-threshold mechanical stimuli and were located mainly in layers I and IIa. Data obtained from 51 pairs of neurons revealed that neurons within a pair often received convergent input from the same types of primary afferent fibers. The paired neurons had overlapping receptive fields, with layer II neurons having smaller receptive fields than layer I neurons and layer II neurons had shorter first-spike latencies than layer I neurons. Some layer II neurons may function as excitatory interneurons and relay primary afferent input to spinothalamic neurons in layer I, where some additional convergence occurs. This conclusion is consistent with observations from Golgi anatomical studies. Layer II neurons responded to noxious heat stimuli with long-latency response components that showed temporal summation and prolonged discharge with repeated stimuli. Central facilitatory mechanisms are generated in layer II neurons that appear to receive direct monosynaptic input from primary nociceptive afferent fibers.