Pressure Control of Sodium Reabsorption and Intercellular Backflux across Proximal Kidney Tubule

Grandchamp, A; Boulpaep, Emile L.

doi:10.1172/jci107751

Cited by 79 publications

(41 citation statements)

References 36 publications

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“…Bicarbonate permeability was 50% higher in volume expansion than in hydropenia. This finding is consistent with the results of Boulpaep, Grandchamp and Boulpaep, and Seely, who found that paracellular resistance was decreased by ECF volume expansion in vivo (21)(22)(23). Berry and Cogan, however, found that bicarbonate permeability was not affected by bath protein removal in the in vitro perfused rabbit proximal tubule (18).…”

Section: Resultssupporting

confidence: 91%

Effects of extracellular fluid volume and plasma bicarbonate concentration on proximal acidification in the rat.

Alpern¹,

Cogan²,

Rector³

1983

J. Clin. Invest.

103

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A B S T R A C T The effects of systemic bicarbonate concentration and extracellular fluid volume status on proximal tubular bicarbonate absorption, independent of changes in luminal composition and flow rate, were examined with in vivo luminal microperfusion of rat superficial proximal convoluted tubules. Net bicarbonate absorption and bicarbonate permeability were measured using microcalorimetry. From these data, net bicarbonate absorption was divided into two parallel components: proton secretion and passive bicarbonate diffusion.The rate of net bicarbonate absorption was similar in hydropenic and volume-expanded rats when tubules were perfused with 24 mM bicarbonate, but was inhibited in volume-expanded rats when tubules were perfused with 5 mM bicarbonate. Volume expansion caused a 50% increase in bicarbonate permeability, which totally accounted for the above inhibition. The rate of proton secretion was unaffected by volume expansion in both studies.The rate of net bicarbonate absorption was markedly inhibited in alkalotic expansion as compared with isohydric expansion. Bicarbonate permeabilities were not different in these two conditions, and the calculated rates of proton secretion were decreased by >50% in alkalosis. Net bicarbonate absorption was stimulated in acidotic rats compared to hydropenic rats. This stimulation was attributable to a 25% increase in the rate of proton secretion.We conclude that (a) proton secretion is stimulatedPortions of this study were presented at the 13th, 14th, and 15th Annual Meetings of the American Society of Nephrology and were published in abstract

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Section: Resultssupporting

confidence: 91%

Effects of extracellular fluid volume and plasma bicarbonate concentration on proximal acidification in the rat.

Alpern¹,

Cogan²,

Rector³

1983

J. Clin. Invest.

103

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“…Our observations that protein removal does not alter JG or JTcO2 are consistent with the view that active sodium transport is not primarily affected and, therefore, agree with one of the major tenets of the Paracellular Backflux Hypothesis. The other major tenet of the Paracellular Backflux Hypothesis predicts that decreased peritubular protein should increase paracellular permeability properties (4,13).…”

Section: Discussionmentioning

confidence: 99%

“…NMany indices of paracellular permeability change with a reduction in peritubular protein in the direction expected. For instance, nonelectrolyte and sodium permeability increase (4,39); PD and electrical resistance decrease (4,13,40), and lateral intercellular space width increases (41).…”

Section: Discussionmentioning

confidence: 99%

“…Several mechanisms whereby peritubular protein mediates the depression in fluid absorption have been postulated (12)(13)(14), but the most widely accepted view is the so-called Paracellular Backflux Hypothesis (1,4,13). According to this view, the regulatory effect of 1Abbreviations used in this manuscript: PCT, proximal protein operates by changing the generalized passive backleak of solutes through the paracellular pathway of the proximal tubule without affecting active transcellular transport.…”

Section: Introductionmentioning

confidence: 99%

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Influence of peritubular protein on solute absorption in the rabbit proximal tubule. A specific effect on NaCl transport.

Berry¹,

Cogan²

1981

J. Clin. Invest.

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A B S T R A C T The effect of removal of peritubular protein on the reabsorption ofvarious solutes and water was examined in isolated rabbit proximal convoluted tubules (PCT) perfused in vitro. In 22 PCT perfused with ultrafiltrate (UF) and bathed in serum, volume absorption (JV) was 1.44 nl/mm per min and potential difference (PD) was -3.6 mV. When these same PCT were bathed in a protein-free UF, JV was reduced 38% without a change in PD. Simultaneous measurements of total CO2 net flux (JTCO2) and glucose efflux (JG) showed that <2% of the decrease in JV could be accounted for by a reduction in JTCO2 and JG, suggesting that removal of peritubular protein inhibited sodium chloride transport (JNacl). Therefore, in eight additional PCT, JNaCl was measured, in addition to PD, JV, JG, and JTCO2. In these PCT, the decrease in total solute transport induced by removal of bath protein was 201.7±37.5 posmol/mm per min. JG decreased slightly (9.1±3.9 posmol/mm per min); NaHCO3 transport did not change (9.2±6.6 posmol/mm per min); but JNac1 decreased markedly (160.6±35.7 posmol/mm per min). 80% of the decrease in JV could be accounted for by a decrease in JNacl. In 13 additional PCT perfused with simple NaCl solutions, a comparable decrease in JV and JNaci was observed when peritubular protein was removed without an increase in TCO2 backleak.

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“…in peritubular capillaries, driving sodium reabsorption in the proximal tubules and potentially contributing to loop diuretic resistance 5,[13][14][15] . Only a few small-scale and largely outdated studies have evaluated combination therapy with acetazolamide in decompensated HF, yet they did show promising results to break loop diuretic resistance 16,17 .…”

Section: Conflict Of Interest: None Declaredmentioning

confidence: 99%

Determinants and impact of the natriuretic response to diuretic therapy in heart failure with reduced ejection fraction and volume overload

et al. 2015

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Pressure Control of Sodium Reabsorption and Intercellular Backflux across Proximal Kidney Tubule

Cited by 79 publications

References 36 publications

Effects of extracellular fluid volume and plasma bicarbonate concentration on proximal acidification in the rat.

Effects of extracellular fluid volume and plasma bicarbonate concentration on proximal acidification in the rat.

Influence of peritubular protein on solute absorption in the rabbit proximal tubule. A specific effect on NaCl transport.

Determinants and impact of the natriuretic response to diuretic therapy in heart failure with reduced ejection fraction and volume overload

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