去甲肾上腺素和刺激隐神经对大鼠体感皮层Ⅰ区神经元自发活动的调制  

MODULATION OF MICROIONTOPHORESED NORADRENALINE AND STIMULATING SAPHENOUS NERVES ON SPONTANEOUS ACTIVITIES OF NEURONS IN RAT PRIMARY SOMATOSENSORY CORTEX

作　　者：胡必利[1] 韩伟[2] 刘甘泉[3] 陈培熹[3] 

机构地区：[1]南华大学基础医学院生理学教研室,衡阳421001 [2]湖南省省怀化医学高等专科学校生理学教研室,41800 [3]中山医科大学生理学教研室,广州510089

出　　处：《中国现代医学杂志》2001年第11期16-18,共3页China Journal of Modern Medicine

基　　金：美国中华医学基金会 (CMB)资助

摘　　要：目的 :探讨去甲肾上腺素是否对体感皮层Ⅰ区神经元的自发活动具有调制作用 ,以及这种调制作用是否影响体感皮层对传入信息的感受。方法 :以SD大鼠为实验对象 ,采用多管玻璃微电极刺激记录技术和微电泳注射的方法 ,观察了不同剂量的去甲肾上腺素和刺激隐神经单独作用和共同作用于体感皮层Ⅰ区神经元时自发活动平均放电率的变化。结果 :去甲肾上腺素能易化体感皮层Ⅰ区电泳部位神经元的自发活动 ,使平均放电率增大。当微电泳电流强度从 5nA逐渐加大至 145nA时 ,平均放电率的增加值从 (0 .5 2± 0 .47)脉冲 /s增大到 (2 4.1± 6 .9)脉冲 /s ,表明易化作用逐渐加强 ,且呈剂量———效应正相关依赖关系。去甲肾上腺素对体感皮层Ⅰ区神经元的自发活动有抑制效应 ,但无剂量依赖关系。刺激隐神经的电流强度较弱 ,单纯A类纤维传入时对记录部位神经元的自发活动有抑制作用 ;刺激强度较强 ,A类和C类纤维共同传入时 ,能易化记录部位的自发活动。而且发现 ,去甲肾上腺素与传入信息对体感皮层Ⅰ区神经元自发活动的调制有相互作用 :去甲肾上腺素既能取消传入信息对体感皮层Ⅰ区神经元自发活动的兴奋效应 ;又能使其抑制作用减弱。结论 :去甲肾上腺素通过调制体感皮层Ⅰ区神经元的自发活动来改变信号一噪声比 。Objective:To Research into the modulation of noradrenaline (NA) and stimulating saphenous nerve on the spontaneous activity of neurons in primary somatosensory cortex and its effects on primary somatosensory cortex percepting afferent signals.Methods:The experiments were performed on the Sprague-Dawley (SD) rats anesthetized with urethance.The signals of the spontaneous activity of neurons in primary somatosensory cortex recorded by multibarreled glass microelectrode were statistically processed by the microcomputer with the mean firing rate (MFR). The changes of spontaneous activity in MFR were comparatively analysed before and during microiontophoresis of NA and electrostimulating saphenus nerve.Results:The spontaneous activity of neurons in primary somatosensory cortex could be facilitated by microiontophoresing NA, which increase the MFRs. When dosages of microiontophoresing NA were gradually increasing from 5 to 145 nA of currents,the increment of MFR rised from 0.52±0.47 spike/s to 24.1±6.9 spike/s, which indicated that the facility effects strengthened gradually, and that there was a positive dose-effect relationship between NA and MFR. The spontaneous activity of neurons in primary somatosensory cortex could be inhibited by microiontophoresing NA, which decrease the MFRs. When current intensity of stimulating saphenus nerve was quite weak, and only type A fibre was afferent, there was an inhibitory effect on the spontaneous activity of neurons in primary somatosensory cortex.When current intensity of stimulating saphenus nerve was fairly strong and type A and C fibres were afferent together, the spontaneous activity of neurons in primary somatosensory cortex was facilitated. There was an interaction between NA and afferent signals in modulating the spontaneous activity of neurons in primary somatosensory cortex: NA could not only suppress the excitation of afferent signals on the spontaneous activity of neurons in primary somatosensory cortex but also decrease its inhibitory effects.Conclusions:NA chang

关 键 词：去甲肾上腺素 体感皮层 神经元 自发活动 调制 

分 类 号：R338.1[医药卫生—人体生理学]