Fig. 5.

Development of cellular networks in the suprachiasmatic nucleus (SCN). a PER2::LUC rhythms in SCN slices at postnatal day (P) 7, P14, and P21 were monitored using a photomultiplier tube (PMT). The SCNs of Cry1^−/−/Cry2^−/− mice exhibit a robust circadian rhythm at P7; the rhythm is gradually dampened and completely undetectable by P21. Wild type SCN exhibits robust rhythms in both neonatal and adult cultures. Data from three littermates are shown for each panel. Vertical lines in the graph indicate 0:00 local time. Numbers on the right margin indicate the age of each SCN culture. b PER2::LUC rhythm of an adult Vipr2^−/−/Cry1^−/−/Cry2^−/− SCN is rescued by co-culturing with neonatal SCN of wild type mice carrying no luciferase reporter on the 5th day of culture (indicated by an arrow). The antagonists for V1a and V1b AVP receptors suppressed the rhythm (gray line), indicating that AVP from the wild type SCN is critical for the coupling of cellular rhythm. Black, vehicle treatment (see Ref. [98])