Micropuncture study in rats with experimental glomerulonephritis

Rocha, Antonino dos Santos; Marcondes, M; Malnic, Gerhard

doi:10.1038/ki.1973.3

Cited by 49 publications

(24 citation statements)

References 23 publications

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“…7r calculated for femoral arterial plasma is taken as representative of wr for the afferent arteriole (7rA). 7r for control rats was calculated from these measured values of C by using the equation: 7r = 1.63C + 0.294C2 (1) where C is expressed in g/100 ml. This equation has been shown by us (24) to agree to within 1% of the more commonly employed empirical equation derived by Landis and Pappenheimer (25).…”

Section: Methodsmentioning

confidence: 99%

“…Recent investigations in several laboratories (1)(2)(3)(4) using an experimental model of acute, proliferative glomerulonephritis in the rat have focused attention on the coupling between single nephron glomerular filtration rate (SNGFR)l and the absolute rate of fluid reab- 1 Abbreviationis uscd in this paper: A/G, albumin/globulin; AP, femoral arterial pressure; APR, absolute rate of fluid reabsorption by the renal proximal tubule; C, protein concentration; CA, CE, afferent and efferent C, respectively; CL, hilar lymph protein concentration; FF, filtration fraction; GBM, glomerular basement membrane; Kr, ultrafiltration coefficient; Kr, reabsorption coefficient; NSN, nephrotoxic serum nephritis; AP, transcapillary hydraulic pressure difference; PC, PE, PGC, PT, hydraulic pressure in peritubular capillaries, efferent arterioles, glomerular capillaries, and proximal tubules, respectively; Pr, net driving force of reabsorption; P1>, driving pressure for ultrafiltration; PUFA, PUFE, net PUF at the afferent and efferent ends, respectively, of the glomerular capillary; 7r, colloid osmotic pressure; Air, transcapillary osmotic pressure difference; sorption by the renal proximal tubule (APR) in this disorder. In each study it was observed that as filtration rate was reduced, the absolute rate of fluid reabsorption to the end of the proximal convoluted tubule was likewise reduced, although not always in proportion to the reduction in SNGFR.…”

Section: Introductionmentioning

confidence: 99%

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Control of proximal tubule fluid reabsorption in experimental glomerulonephritis.

Maddox¹,

Bennett²,

Deen³

et al. 1975

J. Clin. Invest.

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A B S T R A C r We have recently shown that in the early autologous phase of nephrotoxic serum nephritis (NSN) single nephron glomerular filtration rate is unchanged from values in normal hydropenic control rats, but that single nephron filtration fraction and efferent arteriolar oncotic pressure (7rE) are reduced because of a mi rked reduction in the glomerular capillary ultrafiltration coefficient. The present study was undertaken to examine the influence of this decline in 7rE as well as the other known determinants of peritubular capillary fluid exchange on absolute proximal fluid reabsorption (APR) in NSN. The findings indicate that APR and proximal fractional reabsorption are reduced significantly in NSN, relative to values in a separate group of age and weight-matched normal hydropenic control rats studied concurrently. In addition to the measured decline in 7rE, efferent arteriolar plasma flow (QE) and peritubular capillary hydraulic pressure (Pc) were found to increase significantly, while interstitial oncotic pressure. estimated from hilar lymph, was not significantly different from values in control rats. Using a mathematical model of peritubular capillary fluid uptake we found that, assuming that the capillary permeability-surface area product and interstitial hydraulic Portions of these studies were presented at the 7th Annual Meeting of the

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Control of proximal tubule fluid reabsorption in experimental glomerulonephritis.

Maddox¹,

Bennett²,

Deen³

et al. 1975

J. Clin. Invest.

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“…The epithelial aspect of the GBM renmainied relatively free of change, aside from slight and variable fusion of epithelial foot processes (Figs. [6][7][8]. No changes wvere observed in the control rats infused with CFA-stimulated rabbit gamma globulin.…”

Section: Morphologic Changes After Agbm Ab Infusionmentioning

confidence: 99%

“…The NaCl retention could be either the result of increased tubular NaCl and water reabsorption or due to a reduction in filtration rate in all nephrons. Recent studies have suggested that increased NaCl and water reabsorption is not the only or even primary cause for volume retention, which leaves only inimune induced reductions in glomerular filtration to explain the findings (6)(7)(8)(9).…”

Section: Introductionmentioning

confidence: 99%

Acute effects of antiglomerular basement membrane antibody on the process of glomerular filtration in the rat.

Blantz¹,

Wilson²

1976

J. Clin. Invest.

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A B S T R A C T Nephron filtration rate (sngfr) and the factors controlling filtration were examined before and within 60 min of the intravenous infusion of 225-450 Ag of antiglomerular basement membrane antibody (AGBM Ab) (> 50% antigenic saturation) in plasma-expanded (2.5% body wt) Munich-Wistar rats. Pressures in glonmerular capillaries (PG) and Bowman's space (Pt) were measured with a servo-nulling device, systemic (l7rA) and efferent arteriolar oncotic pressures (irE) were measured by microprotein methods, and nephron plasma flow (rpf) and sngfr were measured by micropuncture techniques in both control and post-AGBM Ab conditions in each rat. The sngfr fell from 52.7±2.9 to 24.1±+1.9 nl/min per g kidney wt (n = 7, P <0.001).Both afferent and efferent arteriolar resistances increased and rpf fell from 221±25 to 90±9 nl/min per g kidney wt (P < 0.001) but the hydrostatic pressure gradient across the glomerular membrane (AP = PG -Pt) increased from 37±1 to 50±2 mm Hg (P < 0.001). The increase in AP and a numerical decrease in TA both acted to maintain sngfr after AGBM Ab and effectively nullified the influence of decreased rpf upon sngfr. The nmean effective filtration pressure (EFP = AP -i) increased from 14±2 to 30±3 mm Hg (P < 0.001) while sngfr decreased. The major and critical reason for this reduction in sngfr was a decrease in the glomerular permeability coefficient from 0.077+0.017 to 0.014+0.001 nl/s per g kidney wt per mm Hg (P <0

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“…Godon (8) has demonstrated recently that saline loading fails to reduce fractional sodium reabsorption in rats with glomerulonephritis produced by immunization with glomerular basement membrane. Rocha and coworkers (20) showed increased fractional reabsorption of sodium from the proximal tubule of rats with glomerulonephritis but found that fractional reabsorption of sodium and fluid along the entire nephron was unaltered from that of controls. Decreased G F R resulted in decreased absolute sodium excretion.…”

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confidence: 99%

Micropuncture Study of Fluid Transfer in Aminonucleoside Nephrosis in the Rat

Lewy

1976

Pediatr Res

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ExtractThe present study was designed to assess the relationship be-The relationship between glomerular filtration rate and proximal tubular fluid reabsorption was evaluated in control rats and in rats 96 and 144 hr after the injection of an aminonucleoside of puromycin. Urine volume and sodium excretion were decreased in the rats injected with aminonucleoside. Proteinuria increased progressively. Total kidney glomerular filtration rate (GFR) was diminished less than surface nephron GFR at 96 hr and greater than single nephron GFR at 144 hr after injection when a large proportion of nephrons are nonfunctional. Clearance of p-aminohippurate was unchanged initially and depressed subsequently after aminonucleoside injection. Absolute reabsorption to the end of the proximal convolution was unaltered despite a decrease in total kidney filtration fraction. This decrease in GFR coupled with unchanged absolute reabsorption and hence increased fractional proximal reabsorption leads to decreased delivery of sodium and fluid to the more distal portions of the nephron. SpeculationGlomerular filtration rate is decreased in rats with aminonucleoside nephrosis. Absolute reabsorption along the proximal tubule is not reduced proportionally. The increase in fractional reabsorption which results coupled with a decrease in GFR may be an impoitant source of fluid and sodium retention and thus edema formation in this disease.Since Frenk et a / . (7) reported in 1955 that an aminonucleoside of puromycin ( A M N ) was capable of regularly producing the nephrotic syndrome in the rat, this animal model has served as a useful model to study nlechanisms of proteinuria and edema formation. Edema formation in this disease is a complex interaction of multiple factors (17). However, most investigators have directed their attention to the influence of absolute or relative glomerular insufficiency, tubular preponderance, and hormonal control of sodium and water reabsorption. Edema formation can occur in the absence of aldosterone (I I, 12, 23). In a study by Herken et a/. (I I), intact and adrenalectomized rats with A M N nephrosis, infused orally with isotonic saline, showed decreased G F R and decreased sodium excretion, as well as increased fractional sodium reabsorption. The question of the relative importance of decreased glomerular filtration and increased tubular reabsorption of sodium and water thus was raised in the animal model. Godon (8) has demonstrated recently that saline loading fails to reduce fractional sodium reabsorption in rats with glomerulonephritis produced by immunization with glomerular basement membrane. Rocha and coworkers (20) showed increased fractional reabsorption of sodium from the proximal tubule of rats with glomerulonephritis but found that fractional reabsorption of sodium and fluid along the entire nephron was unaltered from that of controls. Decreased G F R resulted in decreased absolute sodium excretion.tween glomerular filtration and proximal tubular reabsorption of sodium and fluid in A M N nephrosis. Mi...

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Micropuncture study in rats with experimental glomerulonephritis

Cited by 49 publications

References 23 publications

Control of proximal tubule fluid reabsorption in experimental glomerulonephritis.

Control of proximal tubule fluid reabsorption in experimental glomerulonephritis.

Acute effects of antiglomerular basement membrane antibody on the process of glomerular filtration in the rat.

Micropuncture Study of Fluid Transfer in Aminonucleoside Nephrosis in the Rat

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