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The Mouse Isolated Perfused Kidney Technique
Published on: November 17, 2016
Dynamic autoregulation in the in vitro perfused hydronephrotic rat kidney
W A Cupples1, R D Loutzenhiser
1Division of Nephrology and Lady Davis Institute, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec H3T 1E2, Canada.
The American Journal of Physiology
|August 5, 1998
Summary
Renal autoregulation involves tubuloglomerular feedback and a faster myogenic mechanism. This study in hydronephrotic rat kidneys supports the myogenic mechanism as responsible for rapid renal autoregulation dynamics.
Area of Science:
- Physiology
- Nephrology
- Renal Physiology
Background:
- Renal autoregulation maintains stable kidney function via tubuloglomerular feedback (TGF) and a faster myogenic mechanism.
- The precise dynamics and contribution of the myogenic mechanism to renal autoregulation remain incompletely understood.
Purpose of the Study:
- To investigate the dynamic characteristics of renal autoregulation in a hydronephrotic rat kidney model, which lacks TGF.
- To elucidate the role of the myogenic mechanism in the faster component of renal autoregulation.
Main Methods:
- In vitro perfusion of isolated Sprague-Dawley rat kidneys with controlled pressure fluctuations (60-140 mmHg).
- Assessment of renal perfusate flow dynamics using transfer function analysis.
- Evaluation of coherence and admittance gain across a range of frequencies (0.01-0.9 Hz).
Main Results:
- Hydronephrotic kidneys exhibited passive behavior at 60 mmHg and active, pressure-dependent responses at higher pressures.
- High coherence (0.89 +/- 0.03) indicated reliable dynamic responses.
- A resonance peak in admittance gain at ~0.3 Hz and pressure-sensitive gain at lower frequencies (0.01-0.05 Hz) were observed.
Conclusions:
- The observed dynamic responses in hydronephrotic kidneys align with predictions for the myogenic mechanism.
- These findings support the hypothesis that myogenic vasoconstriction mediates the rapid component of renal autoregulation.
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