Summary
Retinal melatonin is synthesized locally and acts as a neuromodulator within the eye, regulated by an intrinsic retinal circadian clock that is entrained by light, independent of pineal melatonin. The interplay between retinal melatonin and dopamine governs light and dark adaptation, suggesting that lighting conditions may have direct local effects on retinal physiology beyond systemic circadian impacts.
Key Findings
- Melatonin synthesis in the retina is elevated at night and reduced during the day, mirroring pineal gland patterns.
- Retinal melatonin does not contribute to circulating plasma levels, indicating it acts solely as a local neuromodulator.
- Retinal circadian rhythms in melatonin synthesis persist in vitro, are entrained by light, and are temperature compensated, confirming an autonomous intraretinal oscillator.
- Melatonin and dopamine levels appear to reciprocally regulate light and dark adaptation in the retina.
Categories
The Science of Light: Examines retinal melatonin synthesis, its circadian regulation, and role as a neuromodulator in retinal physiology including light and dark adaptation.
Sleep & Circadian Health: Describes circadian rhythms in retinal melatonin synthesis entrained by light, relevant to understanding peripheral circadian oscillators.
Eye Health & Vision: Explores melatonin's role in retinal physiology, light/dark adaptation, and its interaction with dopamine in regulating retinal function.
Author(s)
C Gianesini
Publication Year
2015
Related Publications
The Science of Light
- Phototransduction by retinal ganglion cells that set the circadian clock
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- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Melanopsin is required for non-image-forming photic responses in blind mice
Sleep & Circadian Health
- Phototransduction by retinal ganglion cells that set the circadian clock
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- The twoâprocess model of sleep regulation: a reappraisal
- Melanopsin is required for non-image-forming photic responses in blind mice
- Strange vision: ganglion cells as circadian photoreceptors
Eye Health & Vision
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Genetic reactivation of cone photoreceptors restores visual responses in retinitis pigmentosa
- Melanopsin and rodâcone photoreceptors play different roles in mediating pupillary light responses during exposure to continuous light in humans
- Characteristic patterns of dendritic remodeling in early-stage glaucoma: evidence from genetically identified retinal ganglion cell types
- Intrinsically photosensitive melanopsin retinal ganglion cell contributions to the pupillary light reflex and circadian rhythm