Summary
This study demonstrates that dermal melanophores of Xenopus laevis function as peripheral clocks, showing rhythmic expression of melanopsin and core clock genes (per1, per2, bmal1, clock) under light-dark cycles. Melatonin exposure restored clock gene expression patterns in constant-dark conditions to resemble those seen under a 14h:10h light-dark cycle, suggesting melatonin plays a modulatory role in peripheral circadian entrainment.
Key Findings
- Cells maintained in constant darkness for 5 days showed increased mRNA expression of Opn4, per1, per2, bmal1, and clock compared to 14h:10h light-dark conditions.
- A single 1-hour melatonin treatment applied 24 hours before extraction in constant-dark conditions reduced elevated mRNA levels and restored gene expression patterns to those observed under the 14h:10h light-dark cycle.
- Results suggest Xenopus laevis dermal melanophores possess peripheral circadian clock characteristics, with melatonin acting as a key modulator of clock gene expression.
Categories
The Science of Light: Examines melanopsin (Opn4) expression and circadian clock gene regulation (clock, bmal1, per1, per2) in response to light-dark cycles and melatonin in peripheral photoreceptive cells.
Sleep & Circadian Health: Investigates how light-dark cycles and melatonin modulate peripheral circadian clock gene expression, contributing to understanding of entrainment mechanisms.
Author(s)
APC Bluhm
Publication Year
2008
Related Publications
The Science of Light
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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 two‐process 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