Effects of low-power laser irradiation on multiple unit discharges induced by noxious stimuli in the anesthetized rabbit.

This study discusses the effects of low-power laser irradiation upon multiple unit discharges within a peripheral nerve that were induced by a noxious stimulation in anesthetized rabbits. Responding to a pinch stimulation of plantar skin, transitory increase of neuronal discharges was induced in the sural nerve. This was reduced within a minute, and persistent increases, which continued during a period of the stimulation, occurred. These increases became significantly smaller than the control value during a low-power laser irradiation that was applied to the exposed sural nerve distal to the recording site. These results suggested an inhibitory effect of low-power laser irradiation on the impulse conduction within a peripheral nerve. Possible analgesic effects of low-power irradiation are discussed.