The Spike-Like and the Slow Components in Root Potentials

Abstract

Many studies have been reported on the root potentials, since the publication of the first systematic research by Barron and Matthews (1). The essential points, however, namely the structural elements responsible for them and the mechanism of their production, remain still obscure. During the course of investigation on these, the present authors came upon an idea to divide both ventral and dorsal root potentials into two components. The experimental basis of this idea and its bearings on the problem concerning the origin of these potentials are described in the present report.

The Electrical Activities of Single Motoneurones in Toad's Spinal Cord, Recorded With Intracellular Electrodes

“…Iwata and Otani (12) analysed the ventral root potential into two components; the spike-like and the slow. Among them, the spike-like component should be interpreted as a result of an electrotonic spread of syn-aptic potentials set up in motoneurone somata, as assumed in the previous paper (12).…”

The Effect of Tea on the Electrical Activities of Spinal Motoneurons

“…Besides the effect on the action potential, it was shown by Furukawa (8) that tetraethylammonium (TEA) ions had a conspicuous effect of augmenting reflex activities in the toad's spinal cord at a certain stage of their action (see also Iwata and Otani,10).…”

Slow potentials in the dorsal parts of the isolated spinal cord and their relation to dorsal root potentials

“…Kolmodin & Skoglund (1953) found a VRP in such preparations 24 hr after dissection. Iwata & Otani (1952) suggested that in the DRP also there is a superposition of motoneurone effects, especially in its initial maximum part. This assumption does not seem very convincing in view of the present finding that the DRP is well preserved for days and may become even higher in the isolated preparations, at a time when the VRP has disappeared.…”