Authors: Emilio M. Roig, G. Ryan Crislip, I Jeanette Lynch, Charles S. Wingo, and Michelle L. Gumz
Faculty Mentor: Michelle L. Gumz
College: College of Medicine
Heart rate variability (HRV) is an indicator of cardiovascular health. The circadian clock regulates a variety of physiological functions such as HR. The goal of this study was to determine 1) if knockout male mice (KO) lacking a core circadian transcription factor, BMAL1, within distal segments of the kidney affects HRV and 2) if dietary potassium depletion affects HRV. HR in male mice, measured via telemetry, was higher during the active period vs. inactive. Furthermore, KO exhibited a faster HR than control mice. HRV determined by Fourier analysis (Kubios software) demonstrated that there was greater variability during the inactive period vs. active in high frequency bands (PTIME<0.0001) but no genotype differences were found. Additionally, there were no differences in the ratio of low:high frequency regardless of active period or genotype (PTIME=0.4; PGENOTYPE=0.3). HRV was higher during the active period following 5 days of potassium depletion compared to baseline (PTREATMENT<0.01). BMAL1 in renal distal segments does not contribute to variations in beat-to-beat BP. KO exhibit a faster heart rate independent of variability. Potassium depletion increases HRV in this experimental setting. Using this analysis software, changes in BP variability reflected changes in heart rate with faster heart rates correlating with less variability.