蟾蜍离体脊神经节神经元对其外周突与中枢突重复刺激的反应

RESPONSES OF TOAD SPINAL GANGLION NEURONS TO REPETITIVE STIMULATION OF THEIR CENTRAL AND PERIPHERAL PROCESSES

本工作用细胞内记录技术记录了18个蟾蜍离体背根节神经元对其外周突与中枢突刺激的反应。1-2Hz刺激背根和坐骨神经引起的背根节细胞的动作电位参数相同。随着刺激频率增高,30％的细胞对背根和坐骨神经刺激同步地发生动作电位振幅降低、波形分解和脱失;70％的细胞也产生不同程度的变化。背根节细胞对背根和坐骨神经重复刺激不能跟随的频率分别平均为126 Hz和323Hz。结果表明,本工作所记录的背根节细胞为A型神经元,其中枢突的直径小于外周突。对上述变化的可能机制,文中也做了讨论。

Intracellular recordings were made from 48 toad dorsal root ganglion neurons inintro while electrical stimulation was delivered respectively to their dorsal root or sciat-ic nerve input. The average conduction velocities were respectively 12 m/s and15 m/s. With progressively increasing frequency of stimulation, 30% of the record-ed cells showed simultaneous decrease of amplitude, wave decomposition and droppingof propagated response to both inputs while 70% of the cells showed more or less dif-ferent patterns of degradation of the various parameters. Complete failure of neuronsto follow the inputs occured respectively at 126 and 323 Hz. Evidently the dorsalroot ganglion neurons reported in the present work pertain to type A neuron with cen-tral processes smaller in diameter than peripheral ones A possible mechanism underly-ing the different changes is discussed.