Hydrostatic pressure in the subcapsular interstitial space of rat and dog kidneys

Wunderlich, P; Persson, Erik; Schnermann, Jürgen; Ulfendahl, H. R.; Wolgast, M.

doi:10.1007/bf00586833

Cited by 53 publications

(15 citation statements)

References 12 publications

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“…7,11,19 It was shown earlier that the changes in intrarenal NO activity in response to changes in RAP were positively correlated with the changes in U NOx V. 11,12 The commonly used techniques to measure RIHP reported previously include polyethylene matrix capsules 2,15 or microtransducers 4 implanted either acutely or chronically in the renal parenchyma and insertion of a catheter into the subcapsular interstitial space. 17 The subcapsular space is considered a part of the renal interstitium and is in close functional connection with the deeper interstitial space, as it has been shown that injection of labeled albumin into the subcapsular space rapidly appeared in the hilar lymph. 17 The measurement of RIHP from the subcapsular space was preferred to the implantation procedures in the present study to avoid possible tissue injury and tearing of glomerular and peritubular capillaries.…”

Section: Discussionmentioning

confidence: 99%

“…17 The subcapsular space is considered a part of the renal interstitium and is in close functional connection with the deeper interstitial space, as it has been shown that injection of labeled albumin into the subcapsular space rapidly appeared in the hilar lymph. 17 The measurement of RIHP from the subcapsular space was preferred to the implantation procedures in the present study to avoid possible tissue injury and tearing of glomerular and peritubular capillaries. It was reported that pressure in the subcapsular space was in the range of 2 to 7 mm Hg, measured using a micropipette (tip diameter, 1 to 2 m) connected with a polyethylene catheter filled with paraffin oil.…”

Section: Discussionmentioning

confidence: 99%

“…17 This device consists of a microtransducer mounted on the tip of an insulated wire catheter, 4 which can be connected to the recording equipment (model D, Grass Instruments). A small incision was created in the renal capsule for introduction of the catheter transducer, and the opening was then sealed by applying agar.…”

Section: Measurement Of Rihpmentioning

confidence: 99%

“…To assess RIHP, a microtip catheter transducer was placed under the renal capsule. 17 This procedure was preferred because it did not require insertion into the cortical tissue and thus minimized disruption of the renal microcirculation. 4 RIHP and other renal responses were evaluated before and during inhibition of NO synthase by nitro-L-arginine (NLA) and also during renal arterial infusion of NO donors.…”

mentioning

confidence: 99%

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Nitric Oxide Dependency of Arterial Pressure–Induced Changes in Renal Interstitial Hydrostatic Pressure in Dogs

Majid

Said

Omoro

et al. 2001

Circulation Research

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Abstract-A direct relationship between renal arterial pressure (RAP) and renal interstitial hydrostatic pressure (RIHP) has been shown under conditions of efficient renal blood flow autoregulation. Experiments were performed in six anesthetized dogs to evaluate whether these RIHP responses to changes in RAP were modified during nitric oxide (NO) inhibition with nitro-L-arginine (NLA) or after administration of NO donor agents. A microtip catheter transducer was placed underneath the renal capsule to measure RIHP. Stepwise reductions in RAP (140 to 80 mm Hg) during control conditions resulted in decreases in RIHP from its basal value of 4.7Ϯ1.1 mm Hg with a slope of 0.04Ϯ0.026 mm Hg ⅐ mm Hg Ϫ1 along with decreases in urinary nitrate/nitrite excretion rate (U NOx V). Renal cortical and medullary blood flows, measured by laser-Doppler flowmetry, exhibited high autoregulatory efficiency over this RAP range. The changes in RIHP during alterations in RAP were positively correlated (rϭ0.743; PϽ0.001) with the changes in U NOx V but not with cortical or medullary blood flow. NLA infusion decreased RIHP to 1.9Ϯ0.5 mm Hg and also reduced U NOx V from 1.8Ϯ0.2 to 0.9Ϯ0.01 nmol ⅐ min Ϫ1 ⅐ g Ϫ1 . Infusion of NO donors restored RIHP (4.3Ϯ0.9 mm Hg) andDuring NLA infusion, the RIHP responses to reductions in RAP were markedly attenuated and were not restored even during constant-rate infusion of NO donors. The results suggest that changes in RIHP in response to alterations in RAP are associated with changes in intrarenal NO, suggesting a direct effect of NO to regulate RIHP. Key Words: renal regional blood flow Ⅲ laser-Doppler flowmetry Ⅲ nitrate/nitrite excretion P revious studies in dogs and rats have shown that changes in renal arterial pressure (RAP), within the autoregulatory range, are associated with changes in renal interstitial hydrostatic pressure (RIHP), and it has been suggested that these changes in RIHP contribute to the control of tubular reabsorptive function via alterations in the renal interstitial environment. [1][2][3][4][5] The mechanism responsible for RAP-induced changes in RIHP has remained difficult to explain, because renal blood flow (RBF) and peritubular capillary pressure are efficiently autoregulated during alterations in RAP over a wide range. 6 -8 Findings in volume-expanded rats that the renal medullary blood flow (MBF) is more sensitive to changes in RAP than the cortical blood flow (CBF) 9 have led to the suggestion that impaired autoregulatory efficiency of MBF may be linked to the changes in RIHP. 1,10 However, direct associations between changes in RIHP and changes in regional blood flows in the kidney during alterations in RAP have not been established. In addition, studies in dogs as well as in euvolumic rats have failed to demonstrate reduced autoregulatory efficiency of MBF. 6,9,11,12 Inhibition of nitric oxide (NO) synthesis in rats was shown to decrease RIHP and attenuate RIHP responses to changes in renal perfusion pressure. 3 Moreover, selective inhibition of NO in the rat renal med...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Measurement Of Rihpmentioning

confidence: 99%

mentioning

confidence: 99%

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Nitric Oxide Dependency of Arterial Pressure–Induced Changes in Renal Interstitial Hydrostatic Pressure in Dogs

Majid

Said

Omoro

et al. 2001

Circulation Research

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“…Thus the area between the AIr and the AP profiles, denoting the mean net driving force for reabsorption, Pr, was considerably less in NSN than in controls. In both groups, the imbalance between oncotic and hydraulic pressure differences continues to favor net fluid 5Pi in the rat has generally been found to be in the range of 0-4 mm Hg (27,33 Values are expressed as means±1 SE. The number of rats studied is given in parentheses.…”

Section: Discussionmentioning

confidence: 99%

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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Rat renal capsule: Presence of layers of unique squamous cells

Bulger

1973

Anat. Rec.

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Unique squamous cells forming one or more layers are invariably present at the inner border of the rat kidney capsule. The cells frequently surround a space or lumen of irregular contour. The cells appear to be supported by collagenous bundles which run between adjacent cells within groove-like indentations in a single cell, but the connective tissue components are separated from the squamous cells by a thick basal lamina. The fibrous capsule is bound to the renal parenchyma by loose connective tissue containing fibrocytes, small collagen bundles, and abundant mononuclear cells which are partially surrounded by processes of the fibrocytes.

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Hydrostatic pressure in the subcapsular interstitial space of rat and dog kidneys

Cited by 53 publications

References 12 publications

Nitric Oxide Dependency of Arterial Pressure–Induced Changes in Renal Interstitial Hydrostatic Pressure in Dogs

Nitric Oxide Dependency of Arterial Pressure–Induced Changes in Renal Interstitial Hydrostatic Pressure in Dogs

Control of proximal tubule fluid reabsorption in experimental glomerulonephritis.

Rat renal capsule: Presence of layers of unique squamous cells

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