THE EFFECT OF LIGHT WHICH STIMULATE MELANOPSIN-EXPRESSING RETINAL GANGLION CELL INDEPENDENT OF CONE AND ROD ON MELATONIN SUPPRESSION DURING NIGHTTIME

摘要

It has been cleared that melanopsin-expressing retinal ganglion cells (mRGCs) play the important role in the mechanism of circadian rhythm. It is possible that mRGCs contribute greatly to the influence of the light on the melatonin secretion as an expression of circadian rhythm. However there are little reports for the relation between mRGCs and melatonin secretion in humans, because it is difficult to stimulate and measure mRGCs responses independently of cone and rod. The purpose of this study is to clarify the effect of melatonin secretion by light which stimulate only mRGCs using metamerism. The suppressions of salivary melatonin secretion were compared under the two light conditions. Twelve female subjects were exposed to 40% increased (140%) and baseline (100%) mRGCs stimuli (1000lux, 90min) during nighttime, though L-, M-, S-cone stimuli did not changed.