Functional evidence for renorenal reflexes in the rat

Area of Science:

• Nephrology
• Physiology
• Neuroscience

Background:

• The kidney's function is influenced by neural regulation.
• Contralateral effects of renal denervation are not fully understood.
• Volume expansion can alter renal responses.

Purpose of the Study:

• To investigate the functional and hemodynamic changes in the contralateral kidney after acute renal denervation.
• To determine if these changes are mediated by a reflex increase in renal nerve activity.

Main Methods:

• Acute renal denervation was performed in anesthetized, volume-expanded rats.
• Renal function (glomerular filtration rate, p-aminohippurate clearance, urinary volume, sodium excretion) was measured.
• Renal nerve traffic was recorded after contralateral denervation.

Main Results:

• Left renal denervation caused ipsilateral diuresis and natriuresis.
• The contralateral (right) kidney showed decreased glomerular filtration rate, p-aminohippurate clearance, urinary volume, and sodium excretion.
• Prior denervation of the right kidney abolished these contralateral effects.
• Left renal denervation led to a significant, time-dependent increase in nerve traffic to the right kidney.

Conclusions:

• Contralateral renal denervation in volume-expanded rats induces functional changes in the innervated kidney.
• These changes are mediated by a reflex increase in renal nerve activity.
• The interruption of afferent nerve activity from the denervated kidney likely triggers this reflex.