AJP - Renal Physiology, Vol 250, Issue 2 294-F301, Copyright © 1986 by American Physiological Society
Effects of renal denervation on renal responses to hypoxemia in fetal lambs
J. E. Robillard, K. T. Nakamura and G. F. DiBona
The role of renal nerves in mediating renal hemodynamics and renal function
during normal physiological conditions and following moderate hypoxemia was
studied in chronically catheterized fetal lambs (125-141 days of gestation)
following unilateral renal denervation. Base-line values for renal blood
flow (RBF), renal vascular resistance (RVR), glomerular filtration rate
(GFR), urinary flow rate (UFR), urinary electrolyte (Na+, K+, and Cl-)
excretion rate, and urine osmolality (Uosm) were similar in both intact and
denervated kidneys. Hypoxemia was associated with a significant rise in
mean arterial blood pressure and a significant decrease in heart rate.
Hypoxemia produced a similar decrease in GFR and similar increases in
urinary Na+ and Cl- excretion rates in both intact and denervated kidneys.
However, the effect of hypoxemia on renal hemodynamics differed between
intact and denervated kidneys. Hypoxemia produced a continuous and
progressive decrease in RBF and increase in RVR in the intact kidney. On
the other hand, renal denervation was associated with an early renal
vasodilation and attenuated the reduction in RBF and the rise in RVR during
hypoxemia; this early renal vasodilation was blunted following
prostaglandin synthesis inhibition. Taken together, these results suggest
that fetal renal denervation is not associated with significant changes in
renal hemodynamics or renal function during normal physiological conditions
but that renal denervation partially inhibited the renal vasoconstriction
associated with fetal hypoxemia. Finally, it was found that endogenous
prostaglandins counteract the renal vasoconstriction associated with fetal
hypoxemia.
