Day length differently affects daily rhythm gene activity in the brain’s internal clock of Syrian hamsters

Photoperiod significantly affects the expression of clock genes in the suprachiasmatic nuclei of Syrian hamsters.

• All clock genes studied exhibit different expression patterns when exposed to long and short photoperiods.
• Under short photoperiods, Per1, Per2, Per3, and Cry2 show a shorter peak expression duration compared to long photoperiods.
• mRNA expression of Per1, Per3, and Cry1 is advanced in phase under short photoperiods relative to long photoperiods.
• Per3 demonstrates a higher amplitude peak of mRNA expression under short photoperiods, while Per1 and Per2 remain unchanged.
• Bmal1 expression is phase advanced in short photoperiods without a change in duration, and Clock expression displays rhythmicity only under short photoperiods.

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