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Photoperiod differentially regulates circadian oscillators in central and peripheral tissues of the Syrian hamster

Photoperiod differentially regulates circadian oscillators in central and peripheral tissues of the Syrian hamster
Photoperiod differentially regulates circadian oscillators in central and peripheral tissues of the Syrian hamster
In many seasonally breeding rodents, reproduction and metabolism are activated by long summer days (LD) and inhibited by short winter days (SD). After several months of SD, animals become refractory to this inhibitory photoperiod and spontaneously revert to LD-like physiology. The suprachiasmatic nuclei (SCN) house the primary circadian oscillator in mammals. Seasonal changes in photic input to this structure control many annual physiological rhythms via SCN-regulated pineal melatonin secretion, which provides an internal endocrine signal representing photoperiod. We compared LD- and SD-housed animals and show that the waveform of SCN expression for three circadian clock genes (Per1, Per2, and Cry2) is modified by photoperiod. In SD-refractory (SD-R) animals, SCN and melatonin rhythms remain locked to SD, reflecting ambient photoperiod, despite LD-like physiology. In peripheral oscillators, Per1 and Dbp rhythms are also modified by photoperiod but, in contrast to the SCN, revert to LD-like, high-amplitude rhythms in SD-R animals. Our data suggest that circadian oscillators in peripheral organs participate in photoperiodic time measurement in seasonal mammals; however, circadian oscillators operate differently in the SCN. The clear dissociation between SCN and peripheral oscillators in refractory animals implicates intermediate factor(s), not directly driven by the SCN or melatonin, in entrainment of peripheral clocks.
0960-9822
1543-1548
Carr, A.J.
8989b4b9-e986-4599-8595-f17ab2f0c960
Johnston, J.D.
fce92d44-f1d2-4c2a-bd47-f9c5715e3199
Semikhodskii, A.G.
317757af-18b4-413a-b472-23b03e680349
Nolan, T.
1ae43e63-689e-4991-bb1a-c0b0030f654c
Cagampang, F.R.J.A.
7cf57d52-4a65-4554-8306-ed65226bc50e
Stirland, J. Anne
96e3fb71-37ae-4fe4-bb12-9a7d80a51be5
Loudon, A.S.
877c6061-fbe6-4561-9da5-ccafa0cb724c
Carr, A.J.
8989b4b9-e986-4599-8595-f17ab2f0c960
Johnston, J.D.
fce92d44-f1d2-4c2a-bd47-f9c5715e3199
Semikhodskii, A.G.
317757af-18b4-413a-b472-23b03e680349
Nolan, T.
1ae43e63-689e-4991-bb1a-c0b0030f654c
Cagampang, F.R.J.A.
7cf57d52-4a65-4554-8306-ed65226bc50e
Stirland, J. Anne
96e3fb71-37ae-4fe4-bb12-9a7d80a51be5
Loudon, A.S.
877c6061-fbe6-4561-9da5-ccafa0cb724c

Carr, A.J., Johnston, J.D., Semikhodskii, A.G., Nolan, T., Cagampang, F.R.J.A., Stirland, J. Anne and Loudon, A.S. (2003) Photoperiod differentially regulates circadian oscillators in central and peripheral tissues of the Syrian hamster. Current Biology, 13 (17), 1543-1548. (doi:10.1016/S0960-9822(03)00619-5).

Record type: Article

Abstract

In many seasonally breeding rodents, reproduction and metabolism are activated by long summer days (LD) and inhibited by short winter days (SD). After several months of SD, animals become refractory to this inhibitory photoperiod and spontaneously revert to LD-like physiology. The suprachiasmatic nuclei (SCN) house the primary circadian oscillator in mammals. Seasonal changes in photic input to this structure control many annual physiological rhythms via SCN-regulated pineal melatonin secretion, which provides an internal endocrine signal representing photoperiod. We compared LD- and SD-housed animals and show that the waveform of SCN expression for three circadian clock genes (Per1, Per2, and Cry2) is modified by photoperiod. In SD-refractory (SD-R) animals, SCN and melatonin rhythms remain locked to SD, reflecting ambient photoperiod, despite LD-like physiology. In peripheral oscillators, Per1 and Dbp rhythms are also modified by photoperiod but, in contrast to the SCN, revert to LD-like, high-amplitude rhythms in SD-R animals. Our data suggest that circadian oscillators in peripheral organs participate in photoperiodic time measurement in seasonal mammals; however, circadian oscillators operate differently in the SCN. The clear dissociation between SCN and peripheral oscillators in refractory animals implicates intermediate factor(s), not directly driven by the SCN or melatonin, in entrainment of peripheral clocks.

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Published date: 2003
Additional Information: Report

Identifiers

Local EPrints ID: 25349
URI: http://eprints.soton.ac.uk/id/eprint/25349
ISSN: 0960-9822
PURE UUID: 75a02c08-925c-4704-a655-85e3d283974e
ORCID for F.R.J.A. Cagampang: ORCID iD orcid.org/0000-0003-4404-9853

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Date deposited: 12 Apr 2006
Last modified: 08 Jan 2022 02:57

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Contributors

Author: A.J. Carr
Author: J.D. Johnston
Author: A.G. Semikhodskii
Author: T. Nolan
Author: J. Anne Stirland
Author: A.S. Loudon

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