TY - JOUR

T1 - Patterns of blood pressure variability in normotensive and hypertensive rats.

AU - Holstein-Rathlou, N H

AU - He, J

AU - Wagner, A J

AU - Marsh, D J

N1 - Keywords: Activity Cycles; Animals; Blood Pressure; Circadian Rhythm; Fourier Analysis; Hypertension; Hypertension, Renovascular; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Reference Values; Telemetry

PY - 1995

Y1 - 1995

N2 - We sought patterns in mean arterial pressure of normotensive rats and alterations in chronic hypertension. Pressure was recorded for 4-6 days by telemetry from conscious, unrestrained rats and sampled digitally at 3 Hz, using normotensive Sprague-Dawley rats, spontaneously hypertensive rats (SHR), and Sprague-Dawley rats with two-kidney, one-clip renovascular hypertension (2K,1C). Time series analysis was by fast Fourier transform. Power spectra were divided into ultradian (frequencies > 1/day), circadian (frequency = 1/day), and infradian (frequencies < 1/day) domains. In the ultradian band from approximately 0.1 to 10 mHz the spectra were 1/f and without distinct peaks. The slopes were not significantly different among the groups and ranged from -1.03 to -1.61. At frequencies > 10 mHz, power continued to decrease but with a lower slope. A peak centered at approximately 100 mHz was present in both normotensive and 2K,1C rats but not in SHR. SHR had significantly more ultradian power than the others. The circadian rhythm modulated power in the ultradian band. Modulation was most prominent in normotensives, in which the ultradian activity was highest during the night when rats are active and lowest during the day; less pronounced in 2K,1C; and not detectable in SHR. There are regular patterns of blood pressure fluctuations and specific modifications to the patterns by different forms of hypertension.

AB - We sought patterns in mean arterial pressure of normotensive rats and alterations in chronic hypertension. Pressure was recorded for 4-6 days by telemetry from conscious, unrestrained rats and sampled digitally at 3 Hz, using normotensive Sprague-Dawley rats, spontaneously hypertensive rats (SHR), and Sprague-Dawley rats with two-kidney, one-clip renovascular hypertension (2K,1C). Time series analysis was by fast Fourier transform. Power spectra were divided into ultradian (frequencies > 1/day), circadian (frequency = 1/day), and infradian (frequencies < 1/day) domains. In the ultradian band from approximately 0.1 to 10 mHz the spectra were 1/f and without distinct peaks. The slopes were not significantly different among the groups and ranged from -1.03 to -1.61. At frequencies > 10 mHz, power continued to decrease but with a lower slope. A peak centered at approximately 100 mHz was present in both normotensive and 2K,1C rats but not in SHR. SHR had significantly more ultradian power than the others. The circadian rhythm modulated power in the ultradian band. Modulation was most prominent in normotensives, in which the ultradian activity was highest during the night when rats are active and lowest during the day; less pronounced in 2K,1C; and not detectable in SHR. There are regular patterns of blood pressure fluctuations and specific modifications to the patterns by different forms of hypertension.

M3 - Journal article

C2 - 7503315

VL - 269

SP - R1230-9

JO - American Journal of Physiology - Cell Physiology

JF - American Journal of Physiology - Cell Physiology

SN - 0363-6143

IS - 5 Pt 2

ER -