Figure 2

Phase shifting response to light pulses and mRNA accumulation in the SCN. (A) Representative actograms of wild-type (wt) and Syp ^-/- knock-out mice with light pulses at CT10 (top panels), CT14 (middle panels) and CT22 (bottom panels). Blue lines trace activity onset before the light pulse and red lines trace activity onset after the light pulse. (B) Quantification of the phase shifts in Syp ^-/- knock-out (white bar) and wild-type mice (black bar). Syp ^-/- knock-out mice show a significantly reduced phase delay in response to light at CT14 (Syp ^-/- = -34 ± 12 min.; wt = -122 ± 10 min., unpaired t-test p < 0.001 = ***, n = 8 Syp ^-/- and 12 wt). No difference between the genotypes was observed at CT22 (Syp ^-/- = 60 ± 12 min.; wt = 45 ± 6 min., n = 7 Syp ^-/- and 12 wt) and CT10 (Syp ^-/- = 26 ± 12 min.; wt = 21 ± 8 min., n = 7 Syp ^-/- and 11 wt). (C) mRNA accumulation in the SCN of Syp ^-/- knock-out (white bar) and wild-type mice (black bar) before (-) and after (+) a 15 minute light pulse at CT14 or CT22. No differences in expression of cFos, Per1 or Per2 can be observed (n = 3, two-way ANOVA with Bonferroni post-test). Mean values are represented as SEM.