Electrophysiological and relevant morphological properties of neurons in toad dorsal root ganglion

Intracellular recordings were performed on isolated preparations of toad dorsal root ganglion (DRG). Of the 87 neurons examined, 83 were of type A cells and 4 of type C cells. The conduction velocity (CV) of type A cells ranged from 2.55 to 35.19 m/s with a mean of 11.18 +/- 0.78 m/s (mean +/- s mean), while that of type C cells ranged from 1.34 to 2.43 m/s with a mean of 2.11 +/- 0.22 m/s (mean +/- s mean). On the basis of the characteristics of Ap configuration, these 87 cells can be classified into three groups: H neuron (24/87); F neuron (50/87) and F-H neuron (13/87). The Sizes of DRG cells were examined by measuring of HRP labelled cells in part of the experiment. By comparing the size of F and H cell with their CV, we proposed a revised view which is against the public opinion concerning the relation between the size and CV of DRG cells.