Vasoactive intestinal polypeptide requires parallel changes in adenylate cyclase and phospholipase C to entrain circadian rhythms to a predictable phase.

@article{An2011VasoactiveIP,
  title={Vasoactive intestinal polypeptide requires parallel changes in adenylate cyclase and phospholipase C to entrain circadian rhythms to a predictable phase.},
  author={Sungwon An and Robert P. Irwin and Charles N. Allen and Connie Y Tsai and Erik D. Herzog},
  journal={Journal of neurophysiology},
  year={2011},
  volume={105 5},
  pages={2289-96}
}
Circadian oscillations in the suprachiasmatic nucleus (SCN) depend on transcriptional repression by Period (PER)1 and PER2 proteins within single cells and on vasoactive intestinal polypeptide (VIP) signaling between cells. Because VIP is released by SCN neurons in a circadian pattern, and, after photic stimulation, it has been suggested to play a role in the synchronization to environmental light cycles. It is not known, however, if or how VIP entrains circadian gene expression or behavior… CONTINUE READING