Injection of Alkaline Cations into Cat Spinal Motoneurones
Abstract
THE effects of electrophoretic injection of some cations into cat spinal motoneurones have already been reported1. The injection of K+ displaces only the equilibrium potential of the inhibitory post-synaptic potential because of the increased intracellular chloride concentration which is caused by the inward movement of Cl- ions during the flow of the potassium-injecting current. On the other hand, the effects of Na+ injections are characterized by changes in the resting-, spike-, and after-potentials and the inhibitory post-synaptic potential, which can be explained by the intracellular increase of Na+, the reciprocal decrease of K+, and the secondary increase of Cl-. The recovery of these potentials subsequent to a Na+ injection represents the time-course of the sodium extrusion from the motoneurones. According to a recent analysis, the increased intracellular sodium concentration decreases exponentially with a mean time constant of 91 sec; virtually full recovery being attained after about 6 min2. Several other cations have now been injected into cat motoneurones, and this article will describe the effects of injections of Li+, Cs+, and Rb+ ions on the motoneurone potentials and the rates of their removal from the cells.
- Publication:
-
Nature
- Pub Date:
- December 1962
- DOI:
- 10.1038/1961319a0
- Bibcode:
- 1962Natur.196.1319A