Spatiotemporal expression pattern of PERIOD 1 and PERIOD 2 in the mouse SCN is dependent on VIP receptor 2 signaling.

Neurons of the hypothalamic suprachiasmatic nucleus (SCN) express clock genes, which regulate their own transcription and generate daily output signals driving circadian rhythmic behavior and physiology. The neuropeptide VIP and its specific receptor, the VPAC2 receptor, are important for synchronization of clock neurons. In the present study, we characterized PER1 and PER2 expressing neurons in wild-type and VPAC2-deficient mice.