SPIKE POTENTIALS OF THE ELECTROMOTONEURON OF THE ELECTRIC SKATE, NARKE JAPONICA

Abstract

1. Electromotoneurons of the electric lobe were investigated by intracellular electrode technique.
2. Each of the four electric nerves originates from electromotoneurons occupying a particular area in the electric lobe.
3. Antidromic L-spikes and S-spikes were obtained from electromotoneurons and compared with component spikes of the cat motoneurons. The L-spike is presumed to originate from the soma and the proximal segment of electromotoneurons, and the S-spike from the axon remote to the soma.
4. Synaptic potentials of electromotoneurons fluctuate in amplitude at the constant intensity of orthodromic stimulation applied to the surface of the spinal cord. The estimated reversal potential of the synaptic potential was nearly the same as the outside potential of the cell.
5. Intracellular spike potentials of presynaptic fibers were characterized by a high amplitude and a short duration.