Afterdischarge and interactions among fibers in damaged peripheral nerve in the rat

S. J.W. Lisney, M. Devor*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

92 Scopus citations

Abstract

Sensory fibers trapped in nerve-end neuromas become abnormally excitable, and produce an ectopic discharge which is believed to contribute to paresthesias and pain associated with chronic nerve injury in man. Here we report that stimulation of injured nerves can alter this discharge, directly by antidromic invasion of active neuroma fibers, and indirectly through interactions with neighboring fibers. Antidromic stimulation of spontaneously active fibers in experimental neuromas in the rat sciatic nerve, using single electrical stimulus pulses, produced time-locking of rhythmic spontaneous firing and of spontaneous impulse bursts. Some initially silent fibers generated a burst of rhythmic afterdischarge when stimulated in this way. Stimulation delivered in brief trains (tetani) produced more prolonged alterations in spontaneous neuroma discharge, including excitation, suppression and combinations of the two. In some cases initially silent fibers were activated for extended periods. These responses to tetanic stimulation occurred even when the active fibers were not themselves stimulated, and reflect a novel form of fiber-fiber interaction in neuromas that we term 'crossed afterdischarge'. This interaction probably results from the accumulation of potassium ions within the extracellular compartment adjacent to active neuroma fibers during activation of their neighbors. It differs fundamentally from the high safety factor ephaptic cross-talk seen in acutely cut nerves and in neuromas of 30 or more days standing.

Original languageEnglish
Pages (from-to)122-136
Number of pages15
JournalBrain Research
Volume415
Issue number1
DOIs
StatePublished - 7 Jul 1987

Keywords

  • Afterdischarge
  • Nerve fiber cross-talk
  • Nerve injury
  • Nerve pathophysiology
  • Neuroma
  • Pain

Fingerprint

Dive into the research topics of 'Afterdischarge and interactions among fibers in damaged peripheral nerve in the rat'. Together they form a unique fingerprint.

Cite this