Simulation of voltage-gated ion channels behavior during infrared neural inhibition (INI)

Infrared (IR) radiation is a non-invasive method to reduce neural responses, while its mechanism is still unclear. Here, using the modified Hodgkin-Huxley model, the effects of IR light on the parameters participating in the action potential (AP) blocking are investigated to study the mechanism of infrared neural inhibition (INI). Considering the temperature dependence neural model, the voltage membrane changing, ion currents variation and ion channels activation/inactivation gates behavior under IR pulses are studied. The results show that IR pulses can successfully block APs and confirm that potassium ion currents have an influential role in suppressing APs. Moreover, it is shown that infrared light during the suppression of AP has little effect on increasing the sodium ion currents. However, it seems that sodium ion channel gates play an effective role during INI. It is observed that infrared light increases the rate of opening and closing of activation/inactivation gates of ion channels. This study also presents why the suppression of action potentials continues after the end of the IR pulse. It seems this is related to the incomplete refractory period of AP, which is probably due to the disturbance in the reopening of the sodium channel inactivation gate (h-gate). The current report helps to improve the IR laser medical applications for reducing nerve pain.