Baranowski R, Lynn B, Pini A
Br J Pharmacol. 1986 Oct;89(2):267-76. doi: 10.1111/j.1476-5381.1986.tb10256.x.
By examination of compound action potentials in the saphenous nerve of the anaesthetized rat it has been shown that capsaicin causes a rapid, dose-dependent, failure of conduction in many C-fibres when applied directly to the nerve. A large reduction in C-fibre conduction occurs with concentrations as low as 110 microM. After a 15-30 min exposure to capsaicin, only partial recovery occurs in 1 h. Similar block of C-fibre conduction occurs in the ferret. However, only smaller, reversible, reductions in C-fibre conduction were seen in the guinea-pig and rabbit, even at the highest concentration of capsaicin used (33 mM). A small reduction in the A delta component of the compound action potential occurred in all four species. In the rat and ferret the effects were much less than those on C-fibres. At high doses, small reversible effects were also seen on the fastest conducting A alpha beta component of the compound action potential in the rat, rabbit and guinea-pig; no effects were seen on the A alpha beta fibres in the ferret. Decreases in amplitude of the compound action potential were accompanied by some slowing of conduction in most cases. The slowing was less than 5% except for the rat A alpha beta and C-fibres and the ferret C-fibres where 9-15% changes occurred at the highest doses of capsaicin. Opening the connective tissue sheath of the nerve did not significantly increase the effectiveness of capsaicin.
通过检测麻醉大鼠隐神经中的复合动作电位，结果表明，辣椒素直接作用于神经时，可导致许多C纤维迅速出现剂量依赖性传导阻滞。浓度低至110微摩尔时，C纤维传导就会大幅降低。暴露于辣椒素15 - 30分钟后，1小时内仅出现部分恢复。雪貂也出现类似的C纤维传导阻滞。然而，即使在所用辣椒素的最高浓度（33毫摩尔）下，豚鼠和兔子的C纤维传导仅出现较小的、可逆的降低。在所有四个物种中，复合动作电位的Aδ成分均出现小幅降低。在大鼠和雪貂中，其影响远小于对C纤维的影响。高剂量时，大鼠、兔子和豚鼠的复合动作电位中传导最快的Aαβ成分也出现了小的可逆性影响；雪貂的Aαβ纤维未见影响。在大多数情况下，复合动作电位幅度降低的同时伴有一些传导减慢。除大鼠的Aαβ和C纤维以及雪貂的C纤维在辣椒素最高剂量时出现9 - 15%的变化外，传导减慢小于5%。打开神经的结缔组织鞘并未显著提高辣椒素的有效性。
