EFFECTS OF SUSTAINED ELEVATION OF RENAL VENOUS PRESSURE ON SODIUM EXCRETION IN UNANESTHETIZED DOG

Abstract

Renal blood flow, glomerular filtration rate and Na excretion were detd. at intervals in trained unanesthetized dogs before and after the inferior vena cava was partially ligated just above the renal veins. The constriction of the inferior vena cava and consequent elevation of renal venous pressure resulted in an initial proportional reduction of RBF and GFR, and a reduction in Na excretion. One week after inferior vena cava constriction the elevation of renal venous pressure still persisted. In the face of this, RBF, GFR and Na excretion returned to normal. It would appear that, under this experimental condition, no simple cause and effect relationship exists between chronic renal venous pressure elevation and Na excretion in the dog. The implications of these findings in relation to Na retention in congestive heart failure are discussed.