Effects of axotomy on lamprey spinal neurons
Journal
Experimental Neurology
Journal Volume
73
Journal Issue
3
Pages
750-761
Date Issued
1981
Author(s)
Abstract
The central axonal processes of dorsal cells of larval sea lampreys were cut by a high spinal transection. Subsequent histologic changes included a loss of cytoplasmic basophilia, nuclear eccentricity, the development of a perinuclear basophilic shell, and a slight decrease in cell diameter and increase in nuclear diameter resulting in a 26% increase in the ratio of nucleus to cell diameter. These changes were maximal at 3 weeks and were related to the proximity of the cell to the transection site. Electrophysiologic changes included increased input resistance, increased voltage and current thresholds for spike initiation, decreased maximal rate of rise of action potentials, increased spike width, and increased spike overshoot. There was also an increase in axonal conduction velocity and a reduction in resting membrane potential. The electrophysiologic changes tended to lag behind the histologic changes by 1 to 2 weeks and were not clearly related to the proximity of the cell to the transection site. The cellular electrophysiologic changes could result from a decrease in the densities of sodium and potassium channels of the membrane, but there is no evidence yet to support this or any other specific hypothesis. © 1981.
SDGs
Type
journal article