Renal nerve stimulation augments effect of intraluminal angiotensin II on proximal tubule transport.
The proximal tubule synthesizes and secretes angiotensin II into the lumen, where it regulates transport. Renal denervation abolishes the effect of angiotensin II on proximal tubule transport. Using in vivo microperfusion, we examined whether renal nerve stimulation modulates the effect of angiotensin II on transport. The effect of angiotensin II was assessed by measuring the decrease in volume reabsorption with the addition of 10(-4) M luminal enalaprilat. Luminal enalaprilat did not alter volume reabsorption (2.80 +/- 0.18 vs. 2.34 +/- 0.14 nl x mm(-1) x min(-1)). However, with renal nerve stimulation, enalaprilat decreased volume reabsorption (3.45 +/- 0.22 vs. 1.67 +/- 0.20 nl x mm(-1) x min(-1), P < 0.0005). The absolute and percent decrements in volume reabsorption with luminal enalaprilat were higher with renal nerve stimulation than with native innervation (1.78 +/- 0.19 vs. 0.46 +/- 0.23 nl x mm(-1) x min(-1), P < 0.02, and 51.8 +/- 5.0 vs. 14.6 +/- 7.4%, P < 0.05, respectively). Renal nerve stimulation did not alter the glomerular filtration rate or renal blood flow. Renal nerve stimulation augments the stimulatory effect of intraluminal angiotensin II. The sympathetic renal nerves modulate the proximal tubule renin-angiotensin system and thereby regulate proximal tubule transport.
Quan
Albert
A
Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9063, USA. albert.quan@utsothwestern.edu
Baum
Michel
M
D000804:Angiotensin II / Q000008:administration & dosage*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage; D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D004333:Drug Administration Routes; D004558:Electric Stimulation; D015773:Enalaprilat / Q000008:administration & dosage; D005919:Glomerular Filtration Rate / Q000502:physiology; D007668:Kidney / Q000098:blood supply / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D010477:Perfusion; D010525:Peripheral Nerves / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000008:administration & dosage
D000806:Angiotensin-Converting Enzyme Inhibitors; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D015773:Enalaprilat