Effect of acute renal decapsulation on pressure natriuresis in SHR and WKY rats.
The objective of these experiments was to study pressure natriuresis in the Wistar-Kyoto (WKY) and the spontaneously hypertensive rat (SHR) during acute bilateral renal decapsulation, a maneuver that partially blocks the increase in renal interstitial hydrostatic pressure (RIHP). In control WKY rats (n = 7), at renal perfusion pressure (RPP) of 105 +/- 0.7 and 125 +/- 1.1 mmHg, RIHP increased from 4.4 +/- 0.4 to 7.2 +/- 0.7 mmHg (P less than 0.05) and fractional excretion of sodium (FENa) increased from 0.23 +/- 0.05 to 1.32 +/- 0.14% (P less than 0.05). Acute bilateral renal decapsulation (n = 6) blunted the increase in RIHP observed when RPP was increased in control WKY rats and abolished the pressure natriuretic and diuretic response. When RPP was allowed to increase from 106 +/- 0.8 to 130 +/- 2.2 mmHg in the WKY rats with decapsulated kidneys, RIHP increased from 3.8 +/- 0.5 to 4.3 +/- 0.4 mmHg but FENa did not significantly change (0.31 +/- 0.12 to 0.43 +/- 0.13%). In control SHRs (n = 7), at RPPs of 135 +/- 0.8 and 163 +/- 3.0 mmHg, RIHP was 4.4 +/- 0.4 and 5.0 +/- 0.6 mmHg (NS) and FENa was 0.41 +/- 0.10 and 0.82 +/- 0.17% (P less than 0.05). Renal decapsulation in the SHR did not affect the blunted relationships between RPP, RIHP, and FENa; at RPPs of 135 +/- 0.3 and 162 +/- 2.9 mmHg (n = 7), RIHP was 4.4 +/- 0.6 and 4.7 +/- 0.5 mmHg (NS) and FENa was 0.43 +/- 0.10 and 0.95 +/- 0.22% (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Khraibi
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Department of Physiology and Biophysics, Mayo Clinic and Foundation, Rochester, Minnesota 55905.
Knox
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D000818:Animals; D001794:Blood Pressure; D005110:Extracellular Space / Q000502:physiology; D006874:Hydrostatic Pressure; D007668:Kidney / Q000502:physiology*; D008297:Male; D009318:Natriuresis; D011188:Potassium / Q000652:urine; D011312:Pressure; D051381:Rats; D011918:Rats, Inbred SHR / Q000502:physiology*; D011919:Rats, Inbred Strains / Q000502:physiology*; D011921:Rats, Inbred WKY / Q000502:physiology*; D012079:Renal Circulation
D011188:Potassium