The roles of vasoactive intestinal polypeptide in the mammalian circadian clock

Genetic ablation of the VPAC2 receptor disrupts circadian rhythms at multiple levels.

• Circadian rhythms are generated by the master clock in the suprachiasmatic nuclei (SCN) of the hypothalamus.
• The SCN clock is synchronized by environmental signals transmitted through specific neural pathways.
• Vasoactive intestinal polypeptide (VIP) is a key chemical in SCN neurons that responds to light.
• Applying VIP can reset the SCN clock similar to light exposure, both in living organisms and in lab settings.
• The VPAC2 receptor is crucial for both the resetting of the circadian clock by light and the maintenance of its rhythmic function.
• Ablation of the VPAC2 receptor leads to arrhythmic behavior, affecting molecular and neurophysiological aspects of circadian rhythms.

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