The role of slow potassium current in nerve conduction block induced by high-frequency biphasic electrical current.
The role of slow potassium current in nerve conduction block induced by high-frequency biphasic electrical current was analyzed using a lumped circuit model of a myelinated axon based on the Schwarz-Reid-Bostock model. The results indicate that nerve conduction block at stimulation frequencies above 4 kHz is due to constant activation of both fast and slow potassium channels, but the block at stimulation frequencies below 4 kHz could be due to either anodal or cathodal dc block depending on the time of the action potential arriving at the block electrode. When stimulation frequency was above 4 kHz, the slow potassium current was about 3.5 to 6.5 times greater than the fast potassium current at blocking threshold, indicating that the slow potassium current played a more dominant role than the fast potassium current. The blocking location moved from the node under the blocking electrode to a nearby node as the stimulation intensity increased. This simulation study reveals that in mammalian myelinated axons, the slow potassium current probably plays a critical role in the nerve conduction block induced by high-frequency biphasic electrical current.
Liu
Hailong
H
Department of Urology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
Roppolo
James R
JR
de Groat
William C
WC
Tai
Changfeng
C
D000200:Action Potentials; D000465:Algorithms; D000818:Animals; D003198:Computer Simulation; D004558:Electric Stimulation / Q000379:methods*; D008959:Models, Neurological; D009407:Nerve Block / Q000379:methods*; D009431:Neural Conduction; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000502:physiology
D015221:Potassium Channels; D011188:Potassium