Different roles of two brain signals in developing daily rhythm networks after birth

Vasoactive intestinal polypeptide (VIP) signaling is essential for the tissue-level circadian rhythm in the neonatal suprachiasmatic nucleus of CRY double-deficient mice.

• The suprachiasmatic nucleus (SCN) serves as the master circadian clock in mammals.
• Changes in the SCN network are observed postnatally in mice, specifically involving clock gene products.
• In CRY double-deficient mice, both VIP and arginine vasopressin (AVP) signaling contribute redundantly to the circadian rhythm.
• AVP synthesis is significantly reduced in the SCN of CRY double-deficient mice, which may lead to irregular rhythms in adult mice.
• The integration of cellular circadian rhythms in the SCN varies based on the postnatal developmental stage.

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