Summary
This study clarifies that mice lacking functional retinas (and thus unable to entrain to light-dark cycles) can still synchronize behavioral and metabolic rhythms to scheduled feeding, suggesting dopamine neurons of the substantia nigra play a role in food-entrainable circadian rhythms. For lighting and chronobiology applications, the findings reinforce that non-photic zeitgebers like feeding schedules can substitute for light in driving circadian entrainment when retinal pathways are compromised.
Key Findings
- Pitx3 ak mice (lacking functional retinas and most substantia nigra dopamine neurons) failed to entrain behavioral/metabolic rhythms to light-dark cycles, confirming retinal input is required for photic entrainment.
- Contrary to a prior report, Pitx3 ak mice successfully entrained to daily restricted feeding schedules (food available 12h/day), with no observed desynchrony between locomotor, feeding, and metabolic rhythms.
- The residual substantia nigra dopamine neurons surviving in Pitx3 ak mice may represent a minimal dopaminergic population sufficient to support food-anticipatory circadian entrainment.
Categories
Sleep & Circadian Health: Investigates circadian rhythm entrainment to light-dark and feeding schedules in mice with disrupted retinal and dopaminergic systems, with implications for understanding non-photic entrainment mechanisms.
Author(s)
LL Scarpa, B Wanken, M Smidt, RE Mistlberger
Publication Year
2020
Number of Citations
1
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