Simulation of action-potential-sensitive second harmonic generation response of unmyelinated afferents to temperature effects

摘要

Changes in body temperature have clinically significant effects on nerve excitation. However, the mechanisms of these effects still further explored. In this paper, we studied the effects of temperature on the propagation properties of action potential on unmyelinated afferents by action-potential-sensitive second harmonic generation (SHG). A mathematical model was presented which combining with SHG imaging to study the action potential properties in an unmylinated fiber affected by temperature. The results showed that the action potential propagation along an unmyelinated fiber was sensitively probed by optical SHG imaging in real time. Meanwhile, the action potential properties on an unmyelinated fiber is obviously changed at innocuous temperatures through analyzing the changes of action-potential-sensitive SHG signals, including the increase of conduction velocity and the decrease of duration at higher temperatures. Our study indicates that optical second harmonic generation imaging may be a potential tool to investigate the underlying mechanisms of complex physiological phenomena such as nerve excitation.