Micropuncture study of composition of proximal and distal tubular fluid in rat kidney

Ullrich, Karl Julius; Schmidt‐Nielsen, Bodil; O'Dell, Roberta; Pehling, Gundula; Gottschalk, Carl W.; Lassiter, William E.; Mylle, Margaret

doi:10.1152/ajplegacy.1963.204.4.527

Cited by 146 publications

(61 citation statements)

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“…These studies, however, gave no convincing evidence for large reductions in fractional fluid reabsorption in the proximal tubule, nor did they indicate the extent to which more distal sites might be involved. Moreover, both Windhager and Giebisch (8) and Ullrich, Schmidt-Nielsen, O'Dell, Pehling, Gottschalk, Lassiter, and Mylle (9) observed that early distal TP: F sodium ratios were, in fact lower during mannitol infusions; thus the actual load of sodium presented to the distal tubule might be little or no greater than in the control antidiuretic state.…”

Section: Introductionmentioning

confidence: 97%

“…It has also been demonstrated in the rat, under freeflow conditions, that tubule fluid to plasma (TF: P) sodium concentration ratios during hypertonic mannitol infusions fall below unity and tend to approach the value of the limiting gradient at the end of the proximal tubule (8,9). These studies, however, gave no convincing evidence for large reductions in fractional fluid reabsorption in the proximal tubule, nor did they indicate the extent to which more distal sites might be involved.…”

Section: Introductionmentioning

confidence: 99%

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Micropuncture study of hypertonic mannitol diuresis in the proximal and distal tubule of the dog kidney

Seely¹,

Dirks²

1969

J. Clin. Invest.

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A B S T R A C T Fractional reabsorption of water, sodium, and potassium at proximal and distal tubular sites within the nephron was studied by recollection-micropuncture experiments on dogs undergoing hypertonic mannitol diuresis. After an initial control hydropenic phase, 16% mannitol in modified Ringer's solution was administered intravenously, resulting in marked increases in fractional excretion of water (28.7%), sodium (12.6%), and potassium (63.9%). Inulin clearance decreased significantly from 35.1 to 25.2 ml/min. Analysis of paired micropuncture data revealed a significant decrease in tubule fluid to plasma (TF: P) inulin ratios in both the proximal tubule (1.63-1.45) and distal tubule (5.38-1.94). There was also a significant decrease in proximal TF: P sodium ratios (0.99-0.93) and potassium ratios (1.05-0.98). Distal TF: P sodium ratios, in contrast, rose significantly (0.38-0.59), while TF: P potassium ratios tended towards unity whether initially greater or less than one. Fractional reabsorption of sodium and water decreased by 5% and 10% respectively in the proximal tubule, but to a lesser extent than the resulting increases in fractional urinary excretion. The nonreabsorbed fraction, however, had increased sharply at the point of distal puncture for water (32%), sodium (26%), and potassium (26%), indicating a large inhibitory effect within the loop of Henle in addition to the smaller proximal effects.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Micropuncture study of hypertonic mannitol diuresis in the proximal and distal tubule of the dog kidney

Seely¹,

Dirks²

1969

J. Clin. Invest.

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“…Another reason for suspecting that these cells were sensor cells was the fact that they are located very close to the end of the thick ascending limb (TAL). Before the "modern era" of macula densa research in the 1960s, work by Gottschalk and colleagues had found that the [NaCl] of the early distal tubule, that segment just beyond the macula densa, was very low, suggesting that there was salt transport without concomitant water abstraction in the TAL [13]. More importantly, the degree of dilution of tubular fluid was dependent upon the flow rate through this segment [14].…”

Section: Introductionmentioning

confidence: 99%

ATP as a mediator of macula densa cell signalling

Bell

Komlósi

Zhang

2009

Purinergic Signalling

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Within each nephro-vascular unit, the tubule returns to the vicinity of its own glomerulus. At this site, there are specialised tubular cells, the macula densa cells, which sense changes in tubular fluid composition and transmit information to the glomerular arterioles resulting in alterations in glomerular filtration rate and blood flow. Work over the last few years has characterised the mechanisms that lead to the detection of changes in luminal sodium chloride and osmolality by the macula densa cells. These cells are true "sensor cells" since intracellular ion concentrations and membrane potential reflect the level of luminal sodium chloride concentration. An unresolved question has been the nature of the signalling molecule(s) released by the macula densa cells. Currently, there is evidence that macula densa cells produce nitric oxide via neuronal nitric oxide synthase (nNOS) and prostaglandin E 2 (PGE 2 ) through cyclooxygenase 2 (COX 2)-microsomal prostaglandin E synthase (mPGES). However, both of these signalling molecules play a role in modulating or regulating the macula-tubuloglomerular feedback system. Direct macula densa signalling appears to involve the release of ATP across the basolateral membrane through a maxi-anion channel in response to an increase in luminal sodium chloride concentration. ATP that is released by macula densa cells may directly activate P2 receptors on adjacent mesangial cells and afferent arteriolar smooth muscle cells, or the ATP may be converted to adenosine. However, the critical step in signalling would appear to be the regulated release of ATP across the basolateral membrane of macula densa cells.

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“…Chasis & Smith, 1938), dog (e.g. Shannon, 1938) and rat (Ullrich, Schmidt-Nielsen, O'Dell, Pehling, Gottschalk, Lassiter & Mylle, 1963). Changes in potassium and ammonium outputs are more variable in magnitude and even in direction.…”

Section: Introductionmentioning

confidence: 99%

Effects of water diuresis and osmotic (mannitol) diuresis on urinary solute excretion by the conscious rat

Atherton¹,

Hai²,

Thomas³

1968

The Journal of Physiology

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SUMMARY1. The time course and extent of changes in urinary flow and in the outputs of urea, Na+, K+, and NH+ over a period of 71 hr in conscious rats during water and osmotic (mannitol) diuresis were determined, and compared with spontaneous changes in non-diuretic animals.2. In non-diuretic rats, a morning rise and subsequent decline in urinary osmolal, sodium, potassium and ammonium outputs occurred, possibly attributable to circadian rhythms.3. Water diuresis was accompanied by (i) a rapid increase in urea excretion during the phase of increasing urine flow, followed by a fall in later periods to values similar to those in non-diuresis, (ii) a slower increase in sodium output, continuing after the establishment of the constant water load, (iii) unchanged potassium excretion, but slightly increased ammonium outputs.

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Micropuncture study of composition of proximal and distal tubular fluid in rat kidney

Cited by 146 publications

References 1 publication

Micropuncture study of hypertonic mannitol diuresis in the proximal and distal tubule of the dog kidney

Micropuncture study of hypertonic mannitol diuresis in the proximal and distal tubule of the dog kidney

ATP as a mediator of macula densa cell signalling

Effects of water diuresis and osmotic (mannitol) diuresis on urinary solute excretion by the conscious rat

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