PER2::LUC Bioluminescence in ARC/ME Slices

Luminescence was measured from cultured ARC/ME slices of heterozygous PER2::LUC mice as described previously (Yoo et al., 2004 (link)) and Guilding et al., 2009 (link)). Briefly, brains were isolated and harvested in ice-cold Hank’s balanced salt solution (HBSS). 300 µm ARC/ME containing coronal slices (−1.80 mm and −2.10 mm relative to bregma) were prepared using a vibratome (Thermo Scientific, MA, USA). Bilateral ARC/ME regions were further dissected under a dissecting microscope and then immediately placed onto a culture plate insert (Merck Millipore) in 35 mm Petri dishes filled with 1 ml recording medium (same as the one used for cell culture). Luminescence was measured in a LumiCycle (Actimetrics) at 32.5°C.