[Responses of toad spinal ganglion neurons to repetitive stimulation of their central and peripheral processes]

Intracellular recordings were made from 48 toad dorsal root ganglion neurons in vitro while electrical stimulation was delivered respectively to their dorsal root or sciatic nerve input. The average conduction velocities were respectively 12 m/s and 15 m/s. With progressively increasing frequency of stimulation, 30% of the recorded cells showed simultaneous decrease of amplitude, wave decomposition and dropping of propagated response to both inputs while 70% of the cells showed more or less different patterns of degradation of the various parameters. Complete failure of neurons to follow the inputs occurred respectively at 126 and 323 Hz. Evidently the dorsal root ganglion neurons reported in the present work pertain to type A neuron with central processes smaller in diameter than peripheral ones A possible mechanism underlying the different changes is discussed.