Decreased renal perfusion rapidly increases plasma membrane Na-K-ATPase in rat cortex by an angiotensin II-dependent mechanism.
To understand how rapid changes in blood pressure can regulate Na-K-ATPase in the kidney cortex, we tested the hypothesis that a short-term (5 min) decrease in renal perfusion pressure will increase the amount of Na-K-ATPase in the plasma membranes by an angiotensin II-dependent mechanism. The abdominal aorta of anesthetized Sprague-Dawley rats was constricted with a ligature between the renal arteries, and pressure was monitored on either side during acute constriction. Left renal perfusion pressure was reduced to 70 +/- 1 mmHg (n = 6), whereas right renal perfusion pressure was 112 +/- 4 mmHg. In control (nonconstricted) rats (n = 5), pressure to both kidneys was similar at 119 +/- 6 mmHg. After 5 min of reduced perfusion, femoral venous samples were taken for plasma renin activity (PRA) and the kidneys excised. The cortex was dissected, minced, sieved, and biotinylated. Lower perfusion left kidneys showed a 41% increase (P < 0.003) in the amount of Na-K-ATPase in the plasma membrane compared with right kidneys. In controls, there was no difference in cell surface Na-K-ATPase between left and right kidneys (P = 0.47). PRA was 57% higher in experimental animals compared with controls. To test the role of angiotensin II in mediating the increase in Na-K-ATPase, we repeated the experiments (n = 6) in rats treated with ramiprilat. When angiotensin-converting enzyme was inhibited, the cell surface Na-K-ATPase of the two kidneys was equal (P =0.46). These results confirm our hypothesis: rapid changes in blood pressure regulate trafficking of Na-K-ATPase in the kidney cortex.
Yingst
Douglas R
DR
Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA. dyingst@med.wayne.edu
Araghi
Ali
A
Doci
Tabitha M
TM
Mattingly
Raymond
R
Beierwaltes
William H
WH
D000804:Angiotensin II / Q000096:biosynthesis / Q000502:physiology*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D001710:Biotin / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology; D002462:Cell Membrane / Q000201:enzymology*; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000098:blood supply* / Q000201:enzymology*; D008297:Male; D008861:Microsomes / Q000201:enzymology; D017257:Ramipril / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D012079:Renal Circulation / Q000502:physiology*; D012083:Renin / Q000097:blood / Q000502:physiology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D000806:Angiotensin-Converting Enzyme Inhibitors; D000804:Angiotensin II; C052549:ramiprilat; D001710:Biotin; D012083:Renin; D000254:Sodium-Potassium-Exchanging ATPase; D017257:Ramipril