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The renal response to ureteral obstruction.
Scandinavian Journal of Urology and Nephrology. Supplementum
|January 1, 1983
Summary
Investigating ureteral obstruction in rats revealed that the tubuloglomerular feedback (TGF) mechanism is altered, impacting kidney function and blood flow. These changes explain differences in post-obstruction diuresis between unilateral and bilateral ureteral obstruction.
Area of Science:
- Nephrology
- Renal Physiology
- Ureteral Obstruction Pathophysiology
Background:
- Ureteral obstruction significantly impacts renal function.
- The tubuloglomerular feedback (TGF) mechanism, regulating glomerular filtration rate (GFR), is sensitive to interstitial pressure.
- Understanding TGF's role is crucial for elucidating renal pathophysiology during obstruction.
Purpose of the Study:
- To investigate renal pathophysiology during ureteral obstruction in rats.
- To determine the role of the tubuloglomerular feedback (TGF) mechanism in response to obstruction.
- To compare the effects of unilateral ureteral obstruction (UUO) and bilateral ureteral obstruction (BUO) on renal function and TGF sensitivity.
Main Methods:
- Rat experiments involving micropuncture to assess TGF activity, glomerular capillary pressure (PGC), and GFR.
- Measurement of renal interstitial hydrostatic and oncotic pressures.
- Assessment of renal blood flow using microspheres and 86-Rb extraction.
- Administration of indomethacin to study prostaglandin's role.
Main Results:
- Initial ureteral obstruction causes vasodilation mediated by prostaglandins, increasing renal pelvic pressure and PGC.
- Prolonged obstruction leads to progressive vasoconstriction in renal cortex and medulla.
- Two hours of UUO abolished TGF response, while 24h UUO showed high TGF sensitivity.
- Post-obstruction, 2h UUO resulted in reduced GFR due to vasoconstriction and sensitized TGF.
- 24h UUO and BUO exhibited distinct interstitial pressure profiles and TGF sensitivities, potentially explaining differences in post-obstructive diuresis.
Conclusions:
- Prostaglandin release contributes to initial vasodilation during ureteral obstruction.
- Altered interstitial pressure and TGF sensitivity play key roles in the renal response to ureteral obstruction.
- Differences in TGF response and interstitial pressure between UUO and BUO may account for the absence or presence of post-obstructive diuresis.