Ritz L A, Greenspan J D
J Comp Neurol. 1985 Aug 22;238(4):440-52. doi: 10.1002/cne.902380408.
Thirty-six neurons from laminae III-VII in cat sacrocaudal spinal cord were labeled by intracellular injection of horseradish peroxidase, following physiological characterization. Of these 36 neurons, 24 had cell bodies within lamina V. Twelve lamina V neurons were multireceptive; i.e., they responded differentially to innocuous and noxious mechanical stimuli. Most multireceptive neurons had the following morphological features: (1) large cell bodies; (2) extensive dendritic spreads in all directions; and (3) axons which ascended in the contralateral ventral white matter. Three labeled lamina V neurons were activated only by noxious stimuli. Compared to the multireceptive neurons, these nociceptive-specific (NS) units had smaller cell bodies but a similar dendritic spread. Seven lamina V neurons were excited by innocuous mechanical stimuli with no evidence of nociceptive input. These seven neurons had less extensive dendritic trees than the multireceptive and the NS neurons. Six neurons labeled in lamina VII (three multireceptive and three NS) contrasted to most lamina V cells by having smaller cell bodies and short, sparsely branched dendrites. Among the lamina VII neurons, there was no obvious morphological feature that distinguished the multireceptive group from the NS group. Fifteen fully stained neurons from laminae III-VII had late discharges which were correlated with C fiber input. The dendrites of three of these neurons extended into laminae II and I; the dendrites of two neurons reached into the inner portion of lamina II; and the dorsal dendrites of the remaining ten neurons extended no further than the nucleus proprius (laminae III and IV). Thus, deeper dorsal horn neurons evincing reliable, excitatory influences from C fibers do not necessarily have superficially situated dendrites. Tests for correlations between size of cutaneous, excitatory receptive field (RF) and dendritic spread revealed a significant positive correlation between the mediolateral extent of dendritic spread and the size of the low-threshold component of the RF for lamina V neurons.
在对猫骶尾脊髓的生理特性进行表征后，通过细胞内注射辣根过氧化物酶对36个来自III - VII层的神经元进行了标记。在这36个神经元中，24个神经元的细胞体位于V层。12个V层神经元具有多种感受性，即它们对无害和有害的机械刺激有不同的反应。大多数具有多种感受性的神经元具有以下形态特征：（1）大的细胞体；（2）向各个方向广泛伸展的树突；（3）在对侧腹侧白质中上升的轴突。3个标记的V层神经元仅由有害刺激激活。与具有多种感受性的神经元相比，这些伤害性特异性（NS）单位的细胞体较小，但树突伸展情况相似。7个V层神经元受到无害机械刺激的兴奋，没有伤害性输入的证据。这7个神经元的树突分支比具有多种感受性的神经元和NS神经元少。在VII层标记的6个神经元（3个具有多种感受性和3个NS）与大多数V层细胞不同，它们的细胞体较小，树突短且分支稀疏。在VII层神经元中，没有明显的形态特征能将具有多种感受性的组与NS组区分开来。来自III - VII层的15个完全染色的神经元有与C纤维输入相关的晚期放电。其中3个神经元的树突延伸到II层和I层；2个神经元的树突到达II层内部；其余10个神经元的背侧树突延伸不超过固有核（III层和IV层）。因此，显示出C纤维可靠兴奋性影响的更深层背角神经元不一定有位于浅层的树突。对皮肤兴奋性感受野（RF）大小与树突伸展之间相关性的测试表明，V层神经元树突伸展的内外侧范围与RF低阈值成分的大小之间存在显著正相关。
