TY - JOUR
T1 - Differences in dynamic autoregulation of renal blood flow between SHR and WKY rats.
AU - Chen, Y M
AU - Holstein-Rathlou, N H
N1 - Keywords: Animals; Fourier Analysis; Homeostasis; Male; Models, Cardiovascular; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renal Circulation
PY - 1993
Y1 - 1993
N2 - In halothane-anesthetized Wistar-Kyoto (WKY) rats the single-nephron blood flow and the proximal tubule pressure oscillate at a frequency of 35-50 mHz because of the operation of the tubuloglomerular feedback (TGF) mechanism. In spontaneously hypertensive rats (SHR) the oscillations are replaced by chaotic fluctuations. We sought to determine whether this change was associated with a change in the dynamic autoregulation of renal blood flow. In halothane-anesthetized 250- to 320-g SHR and WKY rats, renal blood flow was measured during "white noise" forcing of arterial blood pressure. The frequency response of renal vascular admittance was estimated by the method of autoregressive-moving averages. In the frequency band below 60-70 mHz there was a significant difference in the transfer functions between the two strains of rats. This was due mainly to an increased phase difference, but also to a decreased magnitude of the admittance in SHR at frequencies below 20-30 mHz. Above 70 mHz there was no significant difference in the transfer functions. Because TGF is active in the low frequency band (below approximately 100 mHz), whereas the myogenic mechanism also acts in the higher frequency band, we conclude that the change in the dynamics of TGF leads to a change in the dynamic autoregulation of renal blood flow between SHR and WKY rats. This change results in a more efficient dynamic autoregulation of renal blood flow in the SHR compared with the WKY rats. The functional consequences of this, in terms of the regulation of salt and water excretion, are not presently known.
AB - In halothane-anesthetized Wistar-Kyoto (WKY) rats the single-nephron blood flow and the proximal tubule pressure oscillate at a frequency of 35-50 mHz because of the operation of the tubuloglomerular feedback (TGF) mechanism. In spontaneously hypertensive rats (SHR) the oscillations are replaced by chaotic fluctuations. We sought to determine whether this change was associated with a change in the dynamic autoregulation of renal blood flow. In halothane-anesthetized 250- to 320-g SHR and WKY rats, renal blood flow was measured during "white noise" forcing of arterial blood pressure. The frequency response of renal vascular admittance was estimated by the method of autoregressive-moving averages. In the frequency band below 60-70 mHz there was a significant difference in the transfer functions between the two strains of rats. This was due mainly to an increased phase difference, but also to a decreased magnitude of the admittance in SHR at frequencies below 20-30 mHz. Above 70 mHz there was no significant difference in the transfer functions. Because TGF is active in the low frequency band (below approximately 100 mHz), whereas the myogenic mechanism also acts in the higher frequency band, we conclude that the change in the dynamics of TGF leads to a change in the dynamic autoregulation of renal blood flow between SHR and WKY rats. This change results in a more efficient dynamic autoregulation of renal blood flow in the SHR compared with the WKY rats. The functional consequences of this, in terms of the regulation of salt and water excretion, are not presently known.
M3 - Journal article
C2 - 8430827
SN - 0002-9513
VL - 264
SP - F166-74
JO - American Journal of Physiology
JF - American Journal of Physiology
IS - 1 Pt 2
ER -