Figure 1.

First successful recording of a circadian promoter-driven luminescence rhythm in cultured rodent peripheral tissue. On May 19, 1999, the SCN and skeletal muscle were explanted from a 15 day-old Period1-luciferase rat (L1-line) and cultured with 0.1 mM luciferin. This was our second attempt to record the luminescence rhythm.Bioluminescence was continuously monitored from the SCN (A) and muscle (B) by photo-multiplier tubes (HC135, Hamamatsu) maintained in the incubator at 36°C. Photon counts were recorded at 1-min intervals. C: Photo of the original set-up for bioluminescence recording. It had only two photo-multiplier tubes that were extended to 8 channels.