Lynn B, Shakhanbeh J
Department of Physiology, University College London, U.K.
Neuroscience. 1988 Mar;24(3):769-75. doi: 10.1016/0306-4522(88)90065-6.
The long-term effects of applying capsaicin briefly to a cutaneous nerve in the rabbit have been assessed 10 days after treatment. No changes in C-fibre numbers were seen in treated saphenous nerves and the average ratio of C-fibres to A-fibres was close to 7 in both control and treated nerves. However, the substance P content of the skin innervated by the saphenous nerve fell by 46% after capsaicin treatment compared with a fall of 65% after nerve section. Plasma extravasation in response to 7.5% mustard oil applied to the skin was also reduced following capsaicin treatment (by 43%) and following denervation (by 47%), although the response to 25% mustard oil was unaffected by previous capsaicin treatment. Thus, as in other species that have been examined (notably the rat), brief capsaicin treatment of rabbit skin nerves leads to a reduction in a neurogenic inflammatory response and in substance P content of the skin. However, unlike the rat, there is no degeneration of C-fibres. In the rabbit it is therefore possible to separate the neurotoxic, degenerative action of capsaicin from its ability to deplete substance P. The question of whether a similar dissociation between neurotoxic and other actions could be achieved in the rat by using lower capsaicin concentrations remains to be answered.
在对兔子的皮神经短暂应用辣椒素10天后，已评估了其长期影响。在接受处理的隐神经中未观察到C纤维数量的变化，并且在对照神经和处理后的神经中，C纤维与A纤维的平均比例均接近7。然而，与神经切断后下降65%相比，辣椒素处理后，由隐神经支配的皮肤中P物质含量下降了46%。在应用辣椒素处理后（下降43%）以及去神经支配后（下降47%），对涂抹于皮肤上的7.5%芥子油产生的血浆外渗也减少了，尽管对25%芥子油的反应不受先前辣椒素处理的影响。因此，与已研究的其他物种（特别是大鼠）一样，对兔子皮肤神经进行短暂的辣椒素处理会导致神经源性炎症反应以及皮肤中P物质含量降低。然而，与大鼠不同的是，C纤维没有退化。因此在兔子中，有可能将辣椒素的神经毒性、退行性作用与其消耗P物质的能力区分开来。通过使用较低浓度的辣椒素是否能在大鼠中实现神经毒性与其他作用之间的类似分离，这个问题仍有待解答。
