Clinical neurophysiological study on sensory potential originated from mechanoreceptors

各种机械感受器可对人皮肤的触觉刺激作出反应。本文研究了10名健康志愿者在第三趾尖（FT）、第三趾近节指骨（PP）和鱼际隆起（Pm）分别以100 μm/ms（T100）和400 μm/ms（T400）的速度施加300 μm压痕的触觉刺激所诱发的皮肤感觉电位。通过腕部和肘部的针电极记录正中神经复合感觉动作电位（CSAP），并与电刺激FT后的反应进行比较。电刺激和T400刺激的腕肘间最大感觉传导速度（SNCV）相似，但T100刺激的SNCV平均低15%（P<0.001）。两种压痕速度，SNCV是相似的，无论刺激部位。FT刺激的触觉CSAP的振幅在T400时为1-2 μV，在T100时为0.3-0.4μV。刺激T100诱发的CSAP面积从指尖到近指再到手掌缩小（P<0.05-0.005），而刺激T400诱发的CSAP面积仅在手掌缩小（P<0.05）。结果支持400 μm/ms的快速压痕激活了位于深层的Pacinian小体以及位于表层的Meissner小体，而100 μm/ms的慢速压痕主要激活了Meissner小体。

Various mechanoreceptors may respond to tactile stimulli to the human skin. We investigated sensory potentials from the skin evoked by tactile stimuli with indentations of 300 μm at velocities of 100 (T100) and 400 μm/ms (T400) applied to the tip (FT) and the proximal phalanx of digit III (PP) and the thenar eminence (Pm) of 10 healthy volunteers. We compared with responses after electrical stimulation at FT.Compound sensory action potentials (CSAPs) were recorded from the median nerve through needle electrodes at wrist and elbow. The maximal sensory conduction velocities (SNCVs) between wrist and elbow were similar with electrical and T400 stimulation, but on average were 15% lower with T100 stimulation (P<0.001). With both indentation velocities, SNCVs were similar regardless of stimulation sites. Amplitudes of tactile CSAPs with FT stimulation were 1-2 μV at T400 and 0.3-0.4μV at T100. The CSAP areas evoked by T100 stimulation showed a reduction from fingertip to proximal finger to palm (P<0.05-0.005) whereas those obtained with T400 stimulation showed a reduction only at palm (P<0.05). The results support that fast indentation at 400 μm/ms activated deeply placed Pacinian corpuscles as well as superficially situated Meissner corpuscles, whereas the slower indentation at 100 μm/ms activated primarily Meissner corpuscles.