PT - JOURNAL ARTICLE AU - Bibhudatta Mishra AU - Ross Carson AU - Richard I. Hume AU - Catherine A. Collins TI - Sodium and Potassium Currents Influence Wallerian Degeneration of Injured <em>Drosophila</em> Axons AID - 10.1523/JNEUROSCI.1007-13.2013 DP - 2013 Nov 27 TA - The Journal of Neuroscience PG - 18728--18739 VI - 33 IP - 48 4099 - http://www.jneurosci.org/content/33/48/18728.short 4100 - http://www.jneurosci.org/content/33/48/18728.full SO - J. Neurosci.2013 Nov 27; 33 AB - Axons degenerate after injury and in neuropathies and disease via a self-destruction program whose mechanism is poorly understood. Axons that have lost connection to their cell bodies have altered electrical and synaptic activities, but whether such changes play a role in the axonal degeneration process is not clear. We have used a Drosophila model to study the Wallerian degeneration of motoneuron axons and their neuromuscular junction synapses. We found that degeneration of the distal nerve stump after a nerve crush is greatly delayed when there is increased potassium channel activity (by overexpression of two different potassium channels, Kir2.1 and dORKΔ-C) or decreased voltage-gated sodium channel activity (using mutations in the para sodium channel). Conversely, degeneration is accelerated when potassium channel activity is decreased (by expressing a dominant-negative mutation of Shaker). Despite the effect of altering voltage-gated sodium and potassium channel activity, recordings made after nerve crush demonstrated that the distal stump does not fire action potentials. Rather, a variety of lines of evidence suggest that the sodium and potassium channels manifest their effects upon degeneration through changes in the resting membrane potential, which in turn regulates the level of intracellular free calcium within the isolated distal axon.