蟾蜍脊髓诱发电位性质分析

THE PROPERTIES OF THE EVOKED POTENTIAL IN SPINAL CORD OF TOAD

Araki(1952)[1]首先在蟾蜍离体脊髓标本上记录运动神经元电位,观察突触传递过程,证实了两栖类与哺乳类的突触传递极为相似。后来经常用这个标本研究中枢突触传递。

The purpose of this experiment is to determine the characteristics of the evoked potentials of isolated spinal cord in toad.By exciting the tibialis and the gastrocnemius nerves,both orthodromic(to cut 8-11 th ventral roots)and antidromic(to cut 8-11 th dorsal roots)evoked potentials were recorded from the various sites of white and grey at the level of 9-10 th segments of ipsilateral side of exciting nerves.The routine methods for recording with microelectrode were used in this experiment.The experimental results showed:1.Based on the distribution of the evoked potentials induced by antidromic stimulation on the motoneuron,it was seen that the motoneurons extend their dendrites to the dorsal column 2.The postsynaptic potentials having early and late responses induced by orthodromic stimulation had been recorded at the dorsal column of 9-10 th segments of spinal cord.3.It was demonstrated that the early responses were monosynaptic in nature,Whereas the late responses were disynaptic or polysynaptic in nature.4.The early responses mentioned above represent the exciting effect of monosynaptic synapses formed by muscle spindle afferent nerve contacting with dendrites of motoneuron extending dorsally.