Figure 6. Lack of involvement of the suprachiasmatic nucleus (SCN) in the treadmill exercise-induced phase shift of mouse peripheral clocks.
(a) Experimental schedule. The white and black bars indicate environmental 12 h light and dark conditions. The orange short bar indicates exercise periods. The black arrow indicates the period of measurement using IVIS. Mice with SCN lesions were subjected to IVIS recoding at baseline, and then again after 3 days of treadmill exercise. (b) Comparison of the PER2::LUC expression rhythms of peripheral clocks in mice with SCN lesions before (SCNx-No-Ex; n = 6) or after treadmill exercise (SCNx-T-Ex; n = 6). (c) Plot of rhythmicity and amplitude for each mouse assessed by cosinor analysis. Blue colored symbols are before and red colored symbols are after exercise. Each symbol represents an individual mouse. (d) Ex-vivo experimental schedule. PER2::LUC bioluminescence rhythms from explants of the SCN and the liver. (e) Bioluminescence waveforms of the liver and SCN. (f) Average first peak phase of PER2:LUC rhythms indicated in (e). All values are represented as mean ± SEM (No-Ex, n = 4 and T-Ex, n = 4). *p < 0.05, versus No-Ex, evaluated using a t-test. No exercise or treadmill exercise: No-Ex or T-Ex, respectively.