Comparison of Continuously Collected Urines From the Two Normal Kidneys and Some Effects of Unilateral Denervation

Abstract

A method for chronic continuous urine collection from the two separate kidneys is described. In successful preparations, presumably normal urine may be collected for at least several weeks. The excretions from the two sides are compared and are quite similar, with differences being greatest for sodium excretion. For a variable period following unilateral renal denervation excretion of water, sodium, osmotically active solutes and creatinine may be greater from the denervated kidney than the normal. The differences usually decrease markedly or vanish with time. Any chronic influence of renal denervation in the normal resting dog on sodium excretion, if present, is minor as compared with that of other factors such as mechanically induced unilateral slight fall in GFR, which may result in diminution of sodium output of constricted kidney to only 10 or 20% that of unmolested kidney. Renal vascular sympathetic tone in the resting untraumatized dog is very small or absent within the limits of experimental error.

Blunted diuretic and natriuretic responses to acute sodium loading early after catheter-based renal denervation in normotensive sheep

“…In addition, different experimental paradigms and measurement time points are likely to play a major role. Indeed, at 1 wk post-RDN, any fall in basal production of PRA could potentially be masked by the early natriuresis/diuresis that can occur after RDN (23,39), which could result in a state of compensatory sodium retention. Catheter RDN also had no effect on the increase in PRA in response to a decrease in blood pressure induced by SNP.…”

The Mechanism of Denervation Natriuresis *

“…Sartorius and Burlington (10) studied acute denervation in intact dogs and in isolated kidneys perfused at various pressures. In the data from an intact dog in their Figure 1, the absolute increase in GFR of about 2 Table I). Thus, in most papers concluding that a change in tubular reabsorption follows denervation, the absolute increase in sodium excretion is a fraction of the concurrent absolute increase in filtered sodium.…”

“…Acute or chronic denervation of the kidney results in a moderate increase in electrolyte and water excretion, often described as a "denervation diuresis" (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The mechanism of the natriuresis that is a feature of this phenomenon remains controversial.…”

“…The mechanism of the natriuresis that is a feature of this phenomenon remains controversial. A number of investigators (1)(2)(3)(4)(5) have suggested that nerves alter sodium excretion indirectly by controlling renal hemodynamics, because in their studies there was a rise in filtered sodium large enough to explain the sodium diuresis. Other workers (6)(7)(8)(9)(10)(11)(12) have concluded that denervation depresses tubular transport of sodium.…”

“…When it became apparent that denervation had resulted in a significant increase in sodium excretion (10 minutes to 2.5 hours after denervation), the "denervation" collections were made. A modified Blalock clamp that had been placed around the artery to the denervated kidney 2 was then tightened until UNV E/C was ap- 2 The clamp was positioned before predenervation collections in two experiments, at the time of denervation in proximately equal to the ratio present before denervation. It was usually necessary to reset the clamp several times before the desired sodium excretion ratio was obtained.…”