Key result
Direct renal nerve stimulation reduces RBF ~20% and preserves GFR unlike indirect stimulation.
Why the study?
The effects of renal nerve stimulation on renal hemodynamics, including blood flow, filtration, and sodium excretion, were not fully characterized.
Does direct or indirect renal nerve stimulation alter renal hemodynamics and sodium excretion in anesthetized dogs?
Does direct or indirect renal nerve stimulation alter renal hemodynamics and sodium excretion in anesthetized dogs?
p-value: p=<0.05
This preclinical study demonstrates that changes in sodium excretion following nerve stimulation are not directly related to changes in total RBF, GFR, or intrarenal blood flow distribution, suggesting carotid occlusion effects are not solely mediated by renal nerves.
Renal nerve stimulation reduces RBF without affecting GFR or UNaV in dogs; leaves open neurogenic mechanisms in human cardiorenal disease.
Renal nerves were stimulated either directly (loop electrodes) or indirectly (bilateral carotid occlusion with maintenance of control blood pressure) in anesthetized dogs to determine the effects on renal blood flow (RBF), glomerular filtration rate (GFR), sodium excretion (UNaV), and intrarenal distribution of blood flow (microsphere method). Direct nerve stimulation decreased RBF 20% in 9 of 10 dogs; but GFR, UNaV, and intrarenal distribution of blood flow did not change significantly. Carotid occlusion decreased RBF in 9 of 10 dogs. There was a 22% fall in RBF for the whole group, GFR decreased 33%, and UNaV decreased from 0.39 to 0.17 muEq/min/g (p smaller than 0.05). A small (8%) decrease in midcortical fractional flow (p smaller than 0.05 after carotid occlusion was the only distributional flow change observed. The results disclosed no relationship between changes in sodium excretion and changes in total RBF, GFR, or intrarenal distribution of blood flow following nerve stimulation. These studies also indicate that the renal effects of carotid occlusion are probably not mediated by renal nerve stimulation alone.
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Katz et al. (2008) studied this question. Direct or indirect renal nerve stimulation was evaluated on Renal blood flow (RBF), glomerular filtration rate (GFR), and sodium excretion (UNaV) (p=<0.05). Direct renal nerve stimulation decreased renal blood flow by 20% without changing GFR, whereas indirect stimulation via carotid occlusion decreased RBF by 22%, GFR by 33%, and sodium excretion.
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