Synchronization among mechanisms of renal autoregulation is reduced in hypertensive rats.
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Synchronization among mechanisms of renal autoregulation is reduced in hypertensive rats. / Sosnovtseva, Olga; Pavlov, Alexey N; Mosekilde, Erik; Yip, Kay-Pong; Marsh, Donald J; Holstein-Rathlou, N.-H.
In: American Journal of Physiology - Renal Physiology, Vol. 293, No. 5, 2007, p. F1545-55.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Synchronization among mechanisms of renal autoregulation is reduced in hypertensive rats.
AU - Sosnovtseva, Olga
AU - Pavlov, Alexey N
AU - Mosekilde, Erik
AU - Yip, Kay-Pong
AU - Marsh, Donald J
AU - Holstein-Rathlou, N.-H.
N1 - Keywords: Animals; Arterioles; Feedback, Biochemical; Homeostasis; Hypertension; Kidney; Kidney Glomerulus; Kidney Tubules; Male; Models, Biological; Muscle, Smooth, Vascular; Nephrons; Oscillometry; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Time Factors
PY - 2007
Y1 - 2007
N2 - We searched for synchronization among autoregulation mechanisms using wavelet transforms applied to tubular pressure recordings in nephron pairs from the surface of rat kidneys. Nephrons have two oscillatory modes in the regulation of their pressures and flows: a faster (100-200 mHz) myogenic mode, and a slower (20-40 mHz) oscillation in tubuloglomerular feedback (TGF). These mechanisms interact; the TGF mode modulates both the amplitude and the frequency of the myogenic mode. Nephrons also communicate with each other using vascular signals triggered by membrane events in arteriolar smooth muscle cells. In addition, the TGF oscillation changes in hypertension to an irregular fluctuation with characteristics of deterministic chaos. The analysis shows that, within single nephrons of normotensive rats, the myogenic mode and TGF are synchronized at discrete frequency ratios, with 5:1 most common. There is no distinct synchronization ratio in spontaneously hypertensive rats (SHR). In normotensive rats, full synchronization of both TGF and myogenic modes is the most probable state for pairs of nephrons originating in a common cortical radial artery. For SHR, full synchronization is less probable; most common in SHR is a state of partial synchronization with entrainment between neighboring nephrons for only one of the modes. Modulation of the myogenic mode by the TGF mode is much stronger in hypertensive than in normotensive rats. Synchronization among nephrons forms the basis for an integrated reaction to blood pressure fluctuations. Reduced synchronization in SHR suggests that the effectiveness of the coordinated response is impaired in hypertension.
AB - We searched for synchronization among autoregulation mechanisms using wavelet transforms applied to tubular pressure recordings in nephron pairs from the surface of rat kidneys. Nephrons have two oscillatory modes in the regulation of their pressures and flows: a faster (100-200 mHz) myogenic mode, and a slower (20-40 mHz) oscillation in tubuloglomerular feedback (TGF). These mechanisms interact; the TGF mode modulates both the amplitude and the frequency of the myogenic mode. Nephrons also communicate with each other using vascular signals triggered by membrane events in arteriolar smooth muscle cells. In addition, the TGF oscillation changes in hypertension to an irregular fluctuation with characteristics of deterministic chaos. The analysis shows that, within single nephrons of normotensive rats, the myogenic mode and TGF are synchronized at discrete frequency ratios, with 5:1 most common. There is no distinct synchronization ratio in spontaneously hypertensive rats (SHR). In normotensive rats, full synchronization of both TGF and myogenic modes is the most probable state for pairs of nephrons originating in a common cortical radial artery. For SHR, full synchronization is less probable; most common in SHR is a state of partial synchronization with entrainment between neighboring nephrons for only one of the modes. Modulation of the myogenic mode by the TGF mode is much stronger in hypertensive than in normotensive rats. Synchronization among nephrons forms the basis for an integrated reaction to blood pressure fluctuations. Reduced synchronization in SHR suggests that the effectiveness of the coordinated response is impaired in hypertension.
U2 - 10.1152/ajprenal.00054.2007
DO - 10.1152/ajprenal.00054.2007
M3 - Journal article
C2 - 17728377
VL - 293
SP - F1545-55
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 5
ER -
ID: 8419800