电刺激大鼠腓肠神经引起A_δ、C类传入神经纤维的背根反射

Dorsal root reflex from A_δ and C afferent fibers induced by electrical stimulation of the sural nerve in rats

在距脊髓约 15mm处切断大鼠L5背根 ,将中枢端分成 4～ 5条细束 ,电刺激腓肠神经在背根细束上记录背根反射 (dorsalrootreflex ,DRR)。共记录到DRR 5 1例 ,根据引起DRR所兴奋的腓肠神经纤维类别和DRR在背根逆向传出的纤维类别将DRR分为 5类 :Aαβ Aαβ·DRR、Aβδ Aδ·DRR、Aβδ C·DRR、Aαβδδ C·DRR和C C·DRR。结果证明 ,电刺激外周神经激活各类纤维不但能引起A类 (包括Aδ)纤维的DRR ,而且也能引起C类纤维的DRR。记录的Aδ·DRR和C·DRR为细纤维传入终末产生突触前抑制提供了客观指标 ,为DRR逆向传出冲动到达外周组织 ,释放神经肽类递质 。

The purpose of the study was to investigate whether the small fiber evoked dorsal root reflex (DRR) can be obtained by electrical stimulation of the peripheral nerve in rats. Fifty one DRRs were recorded from different kinds of fiber filaments in the proximal ends of the cut L 5 dorsal root following electrical stimulation of the sural nerve. According to the kind of afferent fibers in the sural nerve associated with the DRRs from dorsal root, these DRRs were divided into five different types: A αβ fiber evoked A αβ ·DRR (A αβ A αβ ·DRR), A βδ A δ·DRR, A βδ C·DRR, A αβδ C·DRR and C C·DRR. The results obtained show that the DRR can be obtained from either A fibers (including A δ fibers) or C fibers of dorsal root filaments by stimulation of the sural nerve. It is therefore suggested that either A δ·DRR or C·DRR can be used as a validity index of presynaptic inhibition of the thin primary afferent terminals for investigation of the modulation mechanisms of peripheral effectors.