Serotonin Modulates Differently the Functional Properties of Damaged and Intact Motoneurons in the Frog Spinal Cord

Abstract

When studying a preparation of the isolated spinal cord segment of an adult frog, damaged and intact lumbar motoneurons were found to differ significantly in the membrane potential, input resistance and the action potential properties (amplitude, duration, fast and medium phases of the afterhyperpolarization, and the frequency of spikes). Serotonin (5-HT) reduced the amplitude of afterpolarization and increased the frequency of the spikes of the intact neurons, while in the damaged motoneurons, 5-HT increased the amplitude of afterpolarization and had no effect on the frequency of discharges.