Brown A G, Fyffe R E, Noble R, Rowe M J
J Physiol. 1984 Sep;354:375-94. doi: 10.1113/jphysiol.1984.sp015382.
The sciatic and saphenous nerves of one hind limb were sectioned in young adult cats anaesthetized with halothane. Between 19 and 55 days later, under chloralose anaesthesia, dorsal horn neurones in the L6 and L7 segments were recorded and their receptive field properties examined. In seven animals recordings were made from identified spinocervical tract, post-synaptic dorsal column and dorsolateral funicular neurones as well as from neurones that did not project through these pathways. Thirty-one neurones were intracellularly stained with horseradish peroxidase, and fifty-three were recorded extracellularly and located by reference to stained cells. In two animals (both 31 days after nerve section) no attempt was made to identify axonal projections of the dorsal horn neurones in order to avoid any effects of cervical cord search stimuli on the cells' properties, but all isolated extracellularly recorded units were examined. On the side ipsilateral to the nerve sections 143 units were recorded. In all experiments, neurones in the medial three-quarters of the dorsal horn had no discernible cutaneous, mechanosensitive receptive fields between 19 and 55 days after nerve section. There were only two exceptions to this generalization, one neurone being one of the most rostral cells in the sample (in caudal L5) and the other being one of the most caudal cells (in caudal L7). We present evidence to show that neither of these two neurones had inappropriate receptive fields in terms of the somatotopic organization of the dorsal horn. All other neurones with receptive fields on the skin were appropriately located in the somatotopic map laid out in the dorsal horn. There was no evidence for gross anatomical changes in the dendritic trees of dorsal horn neurones following sciatic and saphenous nerve sections. We have been unable to confirm that, following loss of cutaneous receptive fields by peripheral nerve section, dorsal horn neurones in adult cats acquire 'inappropriate' receptive fields. Possible reasons for this are discussed.
用氟烷麻醉的成年幼猫，其一侧后肢的坐骨神经和隐神经被切断。在19至55天之后，在氯醛糖麻醉下，记录L6和L7节段的背角神经元，并检查其感受野特性。在7只动物中，对已确定的脊髓颈段束、突触后背柱和外侧索神经元以及未通过这些通路投射的神经元进行了记录。31个神经元用辣根过氧化物酶进行了细胞内染色，53个神经元进行了细胞外记录，并通过参考染色细胞进行定位。在2只动物中（均在神经切断后31天），未尝试确定背角神经元的轴突投射，以避免颈髓搜索刺激对细胞特性的任何影响，但对所有细胞外记录的分离单位进行了检查。在神经切断侧的同侧记录了143个单位。在所有实验中，神经切断后19至55天期间，背角内侧四分之三区域的神经元没有可识别的皮肤机械感受野。这一普遍规律仅有两个例外，一个神经元是样本中最靠前的细胞之一（在L5尾侧），另一个是最靠后的细胞之一（在L7尾侧）。我们提供的证据表明，就背角的躯体定位组织而言，这两个神经元都没有不适当的感受野。所有其他在皮肤上有感受野的神经元都恰当地位于背角的躯体定位图中。没有证据表明坐骨神经和隐神经切断后背角神经元的树突树有明显的解剖学变化。我们无法证实，在成年猫通过外周神经切断失去皮肤感受野后，背角神经元会获得“不适当”的感受野。对此的可能原因进行了讨论。
