Figure 1. Knockout of PER1 in Dahl SS rats exacerbates salt-sensitive hypertension.

(A) Mean arterial pressure (MAP) was determined by averaging daily pressure recordings from 9:00 am to 12:00 pm in SS and SS^Per1−/− rats before and after diet change of 0.4% to 4% NaCl. SS have an N=4 and SS^Per1−/− N=5. *P<0.05 was considered significant. (B) Diurnal blood pressure recordings over the last three days on 0.4% NaCl diet; each point is a 2-hour average. (C) Diurnal blood pressure recordings over the last three days on 4% NaCl diet; each point is a 2-hour average. Shaded regions in B and C indicate the active period when lights are off in the animal facility. Data in B and C were evaluated using two-way RM ANOVA; for data in Panels B, and C, N=4 and 5 for SS and SS^Per1−/− rats, respectively. (D) Rayleigh plots represent a 24-hour clock, with midnight (the midpoint of the active phase for rats) at the top and noon (midpoint of the rest phase) at the bottom. The placement of each dot relative to time on these 24-hour clocks represents the acrophase, or time of peak MAP. The distance of each dot relative to the center represents the amplitude. Error bars represent the 95% confidence interval, with red bars indicating statistically significant variance in acrophase. P-values indicate results from Rayleigh test statistic. For Rayleigh plots, N=4 SS and N=5 SS^Per1−/−.