Hugo Calligaro

DISSECTING THE ROLE OF PHOTORECEPTORS IN THE LIGHT RESPONSE OF THE RETINAL CLOCK IN MAMMALS

The mammalian retina is unique in the circadian system as it contains an endogenous clock that regulates many retinal functions (neurotransmitters synthesis, photoreceptor outer segment recycling…) and tunes the temporal phase of the central clock of the suprachiasmatic nucleus (SCN) to the environmental light/dark cycle. Light entrainment of the SCN involves rods, cones and melanopsin containing retinal ganglion cells (ipRGCs). However, the role of these photoreceptors in the light response of the retinal clock is still controversial. Indeed, if some reports support a role for ipRGCs in retinal light response, recent studies suggest that none of the known photoreceptors is involved in its local entrainment by light.