TY - JOUR

T1 - Tubuloglomerular feedback in Dahl rats.

AU - Karlsen, F M

AU - Leyssac, Paul P.

AU - Holstein-Rathlou, N H

N1 - Keywords: Adaptation, Physiological; Animals; Blood Pressure; Diet, Sodium-Restricted; Drug Resistance; Feedback; Homeostasis; Hydrostatic Pressure; Hypertension; Kidney Glomerulus; Kidney Tubules, Proximal; Loop of Henle; Male; Rats; Rats, Inbred Dahl; Rats, Sprague-Dawley; Reference Values; Sodium Chloride

PY - 1998

Y1 - 1998

N2 - We have previously demonstrated a loss of autoregulation in Dahl salt-sensitive (Dahl-S) rats rendered hypertensive on a high-salt diet. To determine whether this was due to a decreased activity of either the myogenic or the tubuloglomerular feedback (TGF) response, we tested the TGF response in both Dahl-S and salt-resistant Dahl rats on high- and low-salt diets. TGF was investigated in the closed-loop mode with a videometric technique, in which the response in late proximal flow rate to perturbations in Henle flow rate was measured. All Dahl rats showed a similar compensatory response to perturbations around the natural operating point, with a TGF response that was more efficient than in normotensive Sprague-Dawley rats. No evidence of decreased TGF responsiveness in hypertensive Dahl-S rats was found. The results suggest that the loss of autoregulation in hypertensive Dahl-S rats is due to a compromised myogenic response. We also measured the free-flow proximal intratubular pressure in Dahl rats. Perfectly regular oscillations were demonstrated in all Dahl series, including the hypertensive Dahl-S rats. This is the first demonstration of regular oscillations in an experimental rat model of hypertension.

AB - We have previously demonstrated a loss of autoregulation in Dahl salt-sensitive (Dahl-S) rats rendered hypertensive on a high-salt diet. To determine whether this was due to a decreased activity of either the myogenic or the tubuloglomerular feedback (TGF) response, we tested the TGF response in both Dahl-S and salt-resistant Dahl rats on high- and low-salt diets. TGF was investigated in the closed-loop mode with a videometric technique, in which the response in late proximal flow rate to perturbations in Henle flow rate was measured. All Dahl rats showed a similar compensatory response to perturbations around the natural operating point, with a TGF response that was more efficient than in normotensive Sprague-Dawley rats. No evidence of decreased TGF responsiveness in hypertensive Dahl-S rats was found. The results suggest that the loss of autoregulation in hypertensive Dahl-S rats is due to a compromised myogenic response. We also measured the free-flow proximal intratubular pressure in Dahl rats. Perfectly regular oscillations were demonstrated in all Dahl series, including the hypertensive Dahl-S rats. This is the first demonstration of regular oscillations in an experimental rat model of hypertension.

M3 - Journal article

C2 - 9608009

VL - 274

SP - R1561-9

JO - American Journal of Physiology - Cell Physiology

JF - American Journal of Physiology - Cell Physiology

SN - 0363-6143

IS - 6 Pt 2

ER -