The relationship between axonal spike shape and functional modality in cutaneous C-fibres in the pig and rat
The relationship between axonal spike shape and functional modality in cutaneous C-fibres in the pig and rat
复制标题
DOI：
10.1016/s0306-4522(98)00454-0
复制
发表时间：
1999-05-01
期刊：
影响因子：
3.3
通讯作者：
Cotsell, B
中科院分区：
文献类型：
--
作者：
Gee, MD;Lynn, B;Cotsell, B
轴突穗形状进行了检查，确定皮肤C-纤维解剖从麻醉的猪和大鼠的隐神经，并发现不同的功能类。在猪中，愈合伤害感受器单位的动作电位持续时间（半峰振幅持续时间，1.25 +/- 0.16 ms，平均值+/- S.E.M.，n = 32）显著长于多模态伤害性单位的持续时间（0.88 +/-0.11ms，n = 32）。两类伤害性C-纤维的动作电位持续时间长于低阈值机械感受器单位（0.49 +/- 0.04 ms，n = 24）和不可兴奋的C-纤维（0.56 +/- 0.06 ms，n = 19）。下冲持续时间也长于伤害性比非伤害性的C-纤维。与此相反，尖峰幅度是相似的，在所有类别的C-传入。在大鼠中，与猪一样，多模态伤害感受器单位的动作电位持续时间（0.75 +/- 0.05 ms，n = 73）长于机械感受器单位（0.60 +/- 0.01 ms，n = 23）。C纤维被确定为自发活跃的交感传出单位，具有更广泛的动作电位（主起始峰：1.01 +/- 0.12 ms，n = 22;下冲：4.1 +/- 1.23 ms，n = 20）（主峰：0.69 +/-0.03ms，n = 130;下冲：1.4 +/-0.09ms，n = 111）。所有大鼠C-纤维类型的动作电位具有相似高度的主要初始峰。然而，冷的热感受器单位的尖峰与伤害性或不可兴奋的C-fibers.It的结论相比，有明显的差异，轴突尖峰形状之间的不同功能类的C-纤维，特别是，伤害性C-传入往往有轴突动作电位的持续时间比非伤害性传入更长。负责较长持续时间动作电位的离子通道可能为开发高选择性镇痛药物提供靶点。(C)1999年IBRO。出版社：Elsevier Science Ltd
Axonal spike shape was examined in identified cutaneous C-fibres dissected from the saphenous nerves of anaesthetized pigs and rats, and was found to vary with functional class. In the pig, the action potential duration for heal nociceptor units (duration at half peak amplitude, 1.25 +/- 0.16 ms, mean +/- S.E.M., n = 32) was significantly longer than the duration for polymodal nociceptive units (0.88 +/- 0.11 ms, n = 32). Both classes of nociceptive C-fibre had action potentials of longer duration than the low-threshold mechanoreceptor units (0.49 +/- 0.04 ms. n = 24) and the inexcitable C-fibres (0.56 +/- 0.06 ms, n = 19). Undershoot durations were also longer in nociceptive than non-nociceptive C-fibres. In contrast, spike amplitudes were similar in all classes of C-afferent. In the rat, as in the pig, the polymodal nociceptor units had action potentials of longer duration (0.75 +/- 0.05 ms, n = 73) than the mechanoreceptor units (0.60 +/- 0.01 ms, n = 23). C-fibres identified as spontaneously active sympathetic efferent units had wider action potentials (main initial peak: 1.01 +/- 0.12 ms, n = 22; undershoot: 4.1 +/- 1.23 ms, n = 20) than the afferent C-fibres (main peak: 0.69 +/- 0.03 ms, n = 130; undershoot: 1.4 +/- 0.09 ms, n = 111). All rat C-fibre types had action potentials with main initial peaks of a similar height. However, cold thermoreceptor units had spikes with significantly smaller undershoots compared to nociceptive or inexcitable C-fibres.It is concluded that there are clear differences in axonal spike shape between the different functional classes of C-fibre and, in particular, that nociceptive C-afferents tend to have axonal action potentials of longer duration than non-nociceptive afferents. The ion channels responsible for the longer duration action potentials may provide a target for the development of highly selective analgesic drugs. (C) 1999 IBRO. Published by Elsevier Science Ltd.