The internal body clock in young mice brain tissue is very sensitive to outside disturbances

Cultured suprachiasmatic nuclei (SCN) from postnatal day 6 pups show a significantly larger phase shift in circadian rhythm compared to adults.

• Phase shifts in the circadian rhythm were observed in both pups and adults following culture medium exchange.
• The magnitude of the phase shift was significantly larger in pup SCNs than in adult SCNs.
• Half of the pup SCNs did not exhibit consistent circadian rhythms during the initial days in culture.
• Pup SCNs displayed a shorter circadian period and lower amplitude of Bmal1 expression rhythm compared to adults.
• The enhanced responsiveness of cultured SCN in pups may be related to the immaturity of their circadian system's structural organization.

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