Persistent alterations in active and passive electrical membrane properties of regenerated nerve fibers of man and mice

摘要: Excitability of regenerated fibers remains impaired due to changes in both passive cable properties and alterations the voltage-dependent membrane function. These abnormalities were studied by mathematical modeling human nerves experimental studies mice. In three adult male patients with surgically repaired complete injuries peripheral arm 22 months-26 years prior investigation, deviation excitability measures was explained a hyperpolarizing shift resting potential an increase 'Barrett Barrett' conductance (GBB) bridging nodal internodal compartments. associated 'fast' K(+) inward rectifier (GH). Similar found mouse tibial motor axons at 1 month after sciatic crush lesion. During first 5 months regeneration, GH showed partial recovery, which paralleled that GBB. The length remained one-third normal. could be reversed energy-dependent Na(+)/K(+) pump blocker ouabain resulting depolarization. Stressing Na(+) pumping system during strenuous activity protocol triggered Wallerian degeneration but not control from age-matched current data suggest voltage-gated ion channel machinery is restored axons, although electrical separation compartment compromised. Due persistent number nodes, increased activity-dependent influx lead hyperactivity hyperpolarization neurotoxic energy insufficiency activity.