Summary
Green light exposure at just 10 lux produced significant analgesic effects in mice, mediated primarily by cone photoreceptors activating enkephalinergic neurons in the ventrolateral geniculate nucleus (vLGN) and projecting to the dorsal raphe nucleus—not through ipRGCs. These findings suggest that tuning lighting spectra toward green wavelengths at low intensities could be a viable, non-pharmacological pain management strategy in healthcare environments.
Key Findings
- Full-field green light at 10 lux produced significant analgesic effects in both healthy mice and an arthrosis pain model.
- Cone photoreceptor ablation completely abolished the analgesic effect; rod ablation only partially reduced it; ipRGC ablation had no effect.
- Inhibition of the retino-vLGN pathway completely abolished green light analgesia.
- Knockdown of proenkephalin (Penk) in the vLGN or ablation of vLGN-Penk neurons prevented green light analgesia.
- Activation of vLGN-Penk projections to the dorsal raphe nucleus (DRN) was sufficient to suppress nociceptive behaviors, while inhibition of this projection abolished analgesia.
Categories
The Science of Light: Identifies specific photoreceptor types (cones, rods, ipRGCs) and neural circuits mediating green light analgesia, clarifying the mechanistic basis of spectral light effects.
Patient Recovery: Green light exposure at low intensity produced measurable analgesic effects relevant to non-pharmacological pain management in clinical settings.
Author(s)
YL Tang, AL Liu, SS Lv, ZR Zhou, H Cao
Publication Year
2022
Number of Citations
6
Related Publications
The Science of Light
- Phototransduction by retinal ganglion cells that set the circadian clock
- Color appearance models
- 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
Patient Recovery
- Light during darkness and cancer: relationships in circadian photoreception and tumor biology
- An overview of the effects of light on human circadian rhythms: Implications for new light sources and lighting systems design
- Application of different circadian lighting metrics in a health residence
- Melatonin and cortisol in individuals with spinal cord injury
- Sustainable lighting for healthcare facilities: More than just lumens per watt