抄録
1) The electrical properties of the spinal ganglion cell of toads were investigatedwith intracellular microelectrodes.
2) A preamplifier was deviced in order to use one and the same electrode both for recording and for stimulation. The principle and the actual circuit were described.
3) The successful impalement was achieved with microelectrodes of a finer tip and by readjusting the electrode position after penetration of the ganglion cells, judging the condition of the cell membrane by anodal pulses.
4) The resting potential obtained were between 50 and 80mV, and the action potentials 80-125mV.
5) The rising phase of the action potential had two inflection points, suggesting the three-step conduction from the axon to the cell body. Corresponding to them three component potentials of different configuration could be isolated from each other. They were named as S spike, NM spike and M spike.
6) The falling phase of the action potential was followed by an after-positivity, and the relation between its magnitude and the membrane potential was investigated.
7) The rheobasic current and the critical depolarisation for the direct stimulation with the impaled microelectrode were 1.2×10-9 A and 17mV respectively. The rising phase of the directly evoked action potential had in almost all cases one inflection point, suggesting that the non-myelinated segment was first excited and the cell body was activated later.
8) The electrical resistance and capacitance of the cell membrane were measured by applying pulses directly to the cell membrane. The respective values obtained were 2.2Ωcm2. for the cathodal current and 4.0kΩcm2. for the anodal one, and 1.0μF/cm2.
9) For strong hyperpolarising currents the membrane resistance was reduced after it attained to the maximum value, and it took several seconds to recover to the original value after the break of currents.
10) The polarising current affected the membrane activity, and the conduction from M spike to NM spike or from the latter to S spike was blocked by a suitable hyperpolarising current.
