Low Blood Pressure is Independent of Plasma Renin in the Bmal1 Knockout Rat

• Published in: The FASEB journal 2022-05, Vol.36 (S1), p.n/a
• Main Authors: Rhoads, Megan K., Pollock, David M.
• Format: Article
• Language: English
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.2022.36.S1.R2626

Blood pressure (BP) is a crucial physiological parameter that exhibits a circadian rhythm in healthy individuals. Loss of this rhythm is associated with morbidity and mortality. To determine the contribution of the molecular clock to BP regulation, we developed a rat strain with whole body loss of Bmal1 gene expression,a core component of the transcription/translation feedback loop known as the molecular clock. We previously reported that Bmal1‐/‐ rats of both sexes have rhythmic BP, but lower than Bmal1+/+ controls. Given the importance of the renin‐angiotensin system in BP control, we hypothesized that loss of Bmal1 may reduce plasma renin activity in the Bmal1‐/‐ rat. For this experiment, male rats were housed in a 12:12h light/dark cycle with constant humidity and temperature. Water and food (0.49% NaCl) were available ad libitum. BP was measured by a telemetry transmitter implanted in the abdominal aorta of 10‐week‐old rats. After a 10‐day surgical recovery period, BP was recorded for 2 minutes every 10 minutes at 1000 samples/second. Mean BP, assessed by cosinor analysis, was lower in male Bmal1‐/‐ (MBP MESOR: 109±2 mmHg, n=9) animals compared to littermate Bmal1+/+ controls (MBP MESOR: 117±3 mmHg, n=8, p