Crosstalk of the circadian clock, light response, feeding and aging

: Daily rhythms of many physiological and behavioral processes such as sleep and arousal are controlled by the circadian clock. The circadian clock entrains to environmental diurnal changes by using light and food intake as external time cues. Circadian photoentrainment is mediated by retinal ganglion cells expressing a blue-light sensitive photopigment mela- nopsin. Feeding and fasting drive daily rhythms in the expression of circadian clock genes and key regulators of nutrient homeostasis in peripheral tissues. Understanding melanopsin function and timing of feeding-fasting lets us recognize the importance of timing of blue light exposure and feeding based on the concept of the circadian clock, ultimately to adjust the age-related changes in daily rhythm.