Figure 5. Dopamine Shifts the Phase of Retinal PER2::LUC Rhythms.
(A) Application of ADTN (100 μM) along with L-AA (100 μM) beginning at CT 3 advanced PER2::LUC rhythms compared to L-AA (100 μM) application alone.
(B) Application of the D1 receptor agonist SKF 38393 (50 μM) beginning at CT 18 delayed PER2::LUC rhythms compared to vehicle (H2O).
Data shown in (A) and (B) were baseline corrected by calculating a 24-h moving average of the raw data, and then the deviation from the moving average was plotted as a function of days in culture. Bars indicate the duration of treatment.
(C) Phase change following application of dopamine agonists. Briefly, the peak times (as determined by ClockLab software) on the third cycle (after treatment) were subtracted from the peak times on the second cycle (before treatment) for both drug and vehicle, and then used to calculate the phase change of drug versus vehicle controls. Bars show drug phase changes (means ± SEM), error bars from x axis show ±SEM for vehicle controls in each group. Drug concentrations were as follows: ADTN, 100 μM; the D1 agonist SKF 38393, 50 μM; and the D2 agonist quinpirole, 50 μM. Double asterisks (**) indicate p < 0.01, Student's t-test; n = at least 4 for each drug treatment and for vehicle controls.
(D) Lack of phase change following application of melatonin reagents. Phase change was calculated as in (C). Drug concentrations are indicated above columns. Vehicles used for 10 nM melatonin (mel), 10 μM melatonin, and 5 μM luzindole (luz) were 1 μl of 0.01% ethanol, 1 μl of 10% ethanol, and 1 μl of DMSO, respectively; n = at least 4 for each drug treatment and for vehicle controls. No significant effects were observed (p > 0.05 for all).