A Simulation Study on Selective Stimulation of C-Fiber Nerves for Chronic Pain Relief

Abstract

It has been reported that stimulating nociceptive unmyelinated C nerves (C) near the sarcolemma could induce the secretion of endogenous opioids that relieve chronic pain. However, a substantial concern remains: concomitant stimulation might cause acute pain to nociceptive myelinated Aδ nerves (Aδ), which generally have a lower activation threshold than the C. However, few studies have reported on C selectivity over Aδ (C-selectivity). In this study, the C and Aδ nerves were modeled using the Hodgkin-Huxley (HH) and McIntyre-Richardson-Grill (MRG) models, respectively. Two potential stimulation schemes, including bipolar square waves and burst modulated alternating current, together with a new stimulation scheme named inhibit-Aδ (i-Aδ) that inhibits the excitability of theAδ, were systematically investigated. Their stimuli were given to the C and Aδ nerves through point electrodes located near the nerve fibers. Simulation results revealed that i-Aδ presented the highest C-selectivity, which provides a basis for non-invasive effective chronic-pain relief.

Keywords

• Chronic pain
• endogenous opioids
• C-selectivity%22%2C%22default_operator%22%3A%22AND%22%7D%7D%7D"> <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">C</italic>-selectivity
• burst modulated alternating current