Prolonged Light Exposure Induces Circadian Impairment in Aquaporin-4-Knockout Mice

Atsumi Murakami, Kouki Tsuji, Minako Isoda, Masahiro Matsuo, Yoichiro Abe, Masato Yasui, Hitoshi Okamura, Keiko Tominaga

Research output: Contribution to journalLetterpeer-review

2 Citations (Scopus)


Astrocytes are densely present in the suprachiasmatic nucleus (SCN), which is the master circadian oscillator in mammals, and are presumed to play a key role in circadian oscillation. However, specific astrocytic molecules that regulate the circadian clock are not yet well understood. In our study, we found that the water channel aquaporin-4 (AQP4) was abundantly expressed in SCN astrocytes, and we further examined its circadian role using AQP4-knockout mice. There was no prominent difference in circadian behavioral rhythms between Aqp4-/- and Aqp4+/+ mice subjected to light-dark cycles and constant dark conditions. However, exposure to constant light induced a greater decrease in the Aqp4-/- mice rhythmicity. Although the damped rhythm in long-term constant light recovered after transfer to constant dark conditions in both genotypes, the period until the reappearance of original rhythmicity was severely prolonged in Aqp4-/- mice. In conclusion, AQP4 absence exacerbates the prolonged light-induced impairment of circadian oscillations and delays their recovery to normal rhythmicity.

Original languageEnglish
Pages (from-to)208-214
Number of pages7
JournalJournal of Biological Rhythms
Issue number2
Publication statusPublished - 2023 Apr


  • AQP4
  • AQP4-knockout mice
  • circadian rhythm impairment and reappearance
  • circadian rhythms
  • constant light
  • suprachiasmatic nucleus

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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