Conduction in regenerating dorsal root fibres.
Rat dorsal roots were crushed and recordings of compound action potentials and single fibre longitudinal currents were made 12-85 days later from the regenerating portions. Maximum conduction velocities rose from 1.3 m/s at day 10 to 25.7 m/s by day 41 and single fibre velocities varied from 1.2 m/s at 12 days postcrush to 23.8 m/s at 85 days. Many fibres appeared to conduct continuously in the early stages, although the resolution of the technique was insufficient to exclude saltatory conduction over short internodes. Two fibres showed internodes of about 200 microns at 9 and 13 days of regeneration, suggesting that "nodal" regions may be formed before significant myelination. At 27 days post-crush and later, internodes were 300-425 microns in length. Many regenerating fibres had branches, both retrograde and orthograde. Reduced conduction velocities in rostral portions of regenerating fibres suggested tapering.
D000818:Animals; D005727:Ganglia, Spinal / Q000502:physiology*; D007473:Ion Channels / Q000378:metabolism; D008564:Membrane Potentials; D009409:Nerve Crush; D009413:Nerve Fibers, Myelinated / Q000502:physiology; D009416:Nerve Regeneration; D009431:Neural Conduction; D011901:Ranvier's Nodes / Q000502:physiology; D051381:Rats
D007473:Ion Channels