人体桡神经浅支支配机械感受性单位的生理学特征

实验用神经内微记录和微刺激相结合的方法,对人体桡神经浅支支配的有毛皮肤所属机械感受性单位的特征和诱发感觉的性质进行了观察。在47个感觉单位中,SA单位占74.5%,其中SAⅠ61.7%,SAⅡ12.8%,RA单位占25.5%,没有发现毛囊单位和PC单位。SA单位的平均机械阈值高于RA单位,RA和SAⅠ单位的感受野明显小于SAⅡ单位。神经内微刺激诱发感觉的性质取决于所兴奋单位的类型,RA单位产生间断的跳动感,SAⅠ单位产生持续的压感;而SAⅡ单位在单独兴奋时不产生特定的感觉。结果提示:人体桡神经浅支支配的有毛皮肤机械感受性单位的特征与无毛皮肤没有明显差别。

PHYSIOLOGICAL CHARACTERISTICS OF SUPERFICIAL BRANCH OF THE RADIAL NERVE INNERVATING MECHANORECEPTIVE UNITS IN THE HUMAN BODY

By means of intraneural microrecording (IN-MR) and intraneural microstimulation (INMS),the characteristics of hairy skin's mechanoreceptiveunits innervated by superficial branch of radial nerve andthe sensations mediated by the nerve were ob-served on the awaking human body. A total of 47mechanoreceptive units were identified, 35 of them(74. 5%) were classified as SA units and 12 ofthem (25. 5%) as RA units, hair-follicle unit andPC unit were not found in experiments. The aver-age mechanical thresholds of SA units were some-what higher than those of RA units, receptivefields of RA and SA Ⅰ units were significantlysmaller than those of SA Ⅱ units. The type of unitexcited by INMS determined the sensations quali-y, RA units evoked intermittent tapping, SA Ⅰ u-nits evoked sustained pressure; SA Ⅱ units evokedno particular sensation when activated in isolation.The results indicate that the characteristics of themechanoreceptive units in the hairy skin do not differ from those in the glabrous skin at the humanbody.