Single nephron filtration rates (SNGFR) in the trout,Salmo gairdneri

1978 ◽  
Vol 377 (1) ◽  
pp. 101-108 ◽  
Author(s):  
J. Anne Brown ◽  
B. A. Jackson ◽  
J. Ann Oliver ◽  
I. W. Henderson
Keyword(s):  
Salmo Gairdneri ◽  
Single Nephron ◽  
Single Nephron Filtration Rates

Evaluation of methods of measuring glomerular and nutrient blood flow in rat kidneys

1978 ◽  
Vol 235 (5) ◽  
pp. H592-H600 ◽  
Author(s):  
W. E. Yarger ◽  
M. A. Boyd ◽  
N. W. Schrader
Keyword(s):  
Blood Flow ◽  
Plasma Flow ◽  
Outer Cortex ◽  
Flow Rates ◽  
Cortical Blood Flow ◽  
Medullary Blood Flow ◽  
Single Nephron ◽  
Inner Cortex ◽  
Single Nephron Filtration Rates ◽  
Evaluation Of Methods

In normal rats, glomerular plasma flow rates (GPF) were estimated from the uptake of microspheres, and single-nephron filtration rates were estimated by Hanssen's technique in order to calculate single-nephron filtration fractions (SNFF) for outer (C1), middle, (C2), and deep (C3) nephrons. With large microspheres (15 micron), SNFF averaged 0.19, 0.41, and 0.63, and with small microspheres (9 micron), SNFF averaged 0.25, 0.48, and 0.42 for areas C1, C2, and C3, respectively. Kidney filtration fractions (FF) averaged 0.36. Because microsphere experiments in normal rats have generally suggested that SNFF-C1 and FF are similar, we conclude that both types of microspheres overestimated outer cortical plasma flow rates, and probably underestimated inner cortical plasma flow rates. In addition, not all of the smaller microspheres were trapped in the glomeruli. Nutrient blood flow rates were estimated from the uptake of 86Rb. Values ranged from 7.3 ml/g per min in the outer cortex to 4.7 ml/g per min in the inner cortex. Because these values are very similar to measurements made by several other techniques, we conclude that 86Rb uptake adequately estimates cortical blood flow. Medullary blood flow estimates, however, increased with time and were probably too high.

A computational model for emergent dynamics in the kidney

2009 ◽  
Vol 367 (1896) ◽  
pp. 2125-2140 ◽  
Author(s):  
Robert Moss ◽  
Ed Kazmierczak ◽  
Michael Kirley ◽  
Peter Harris
Keyword(s):  
Computational Model ◽  
Network Model ◽  
Tubuloglomerular Feedback ◽  
Exchange Mechanism ◽  
Model Complex ◽  
Wide Range ◽  
Countercurrent Exchange ◽  
Single Nephron ◽  
The Stability ◽  
Single Nephron Filtration Rates

In this paper, concepts from network automata are adapted and extended to model complex biological systems. Specifically, systems of nephrons , the operational units of the kidney, are modelled and the dynamics of such systems are explored. Nephron behaviour can fluctuate widely and, under certain conditions, become chaotic. However, the behaviour of the whole kidney remains remarkably stable and blood solute levels are maintained under a wide range of conditions even when many nephrons are damaged or lost. A network model is used to investigate the stability of systems of nephrons and interactions between nephrons. More sophisticated dynamics are explored including the observed oscillations in single nephron filtration rates and the development of stable ionic and osmotic gradients in the inner medulla which contribute to the countercurrent exchange mechanism. We have used the model to explore the effects of changes in input parameters including hydrostatic and osmotic pressures and concentrations of ions, such as sodium and chloride. The intrinsic nephron control, tubuloglomerular feedback, is included and the effects of coupling between nephrons are explored in two-, eight- and 72-nephron models.

Angiotensin and single nephron glomerular function in the trout Salmo gairdneri

1980 ◽  
Vol 239 (5) ◽  
pp. R509-R514 ◽  
Author(s):  
J. A. Brown ◽  
J. A. Oliver ◽  
I. W. Henderson ◽  
B. A. Jackson
Keyword(s):  
Glomerular Filtration Rate ◽  
Angiotensin Ii ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Salmo Gairdneri ◽  
Glomerular Function ◽  
Tubular Lumen ◽  
Single Nephron ◽  
Renal Tubular Transport ◽  
Renal Tubular

Glomerular filtration rate (GFR), urine flow (UV), renal tubular transport maximum for glucose (TMG), and single nephron glomerular filtration rate (SNGFR), determined in anesthetized norepinephrine-infused trout (Salmo gairdneri), were 18.51 +/- 5.78 microliter x min-1 x kg body wt-1, 5.31 +/- 1.38 microliter x min-1 x kg body wt-1, 105.21 +/- 46.84 microgram x min-1 x kg body wt-1, and 3.74 +/- 1.12 nl/min, respectively, when in seawater (SW) and 140.39 +/- 17.24, 76.38 +/- 10.41, 626.16 +/- 77.46, and 1.31 +/- 0.20 in freshwater (FW). Angiotensin II infusions, to reduce UV, GFR, and TMG by 50%, had no effect on the average SNGFR of FW trout, but reduced that of SW fish to 1.42 +/- 0.19 nl/min. Infusions of 20% ferrocyanide, visualized as Prussian blue (PB), identified three glomerular populations: filtering (F) with PB in glomerular vessels and tubular lumen; nonfiltering (NF)--PB in glomerular vessels only; nonperfused (NP)--no PB associated with the nephron. SW and FW kidneys contained about 40% NF tubules. In FW, 45% were F tubules compared with 5% in SW, whereas NP tubules comprised 51% of SW tubules and 13% of FW. During angiotensin II infusions the distributions were 9% and 46% NF in FW and 6% F and 12% NF in SW trout.

Single-nephron filtration rate and proximal reabsorption in aging rats

1991 ◽  
Vol 260 (1) ◽  
pp. F75-F80 ◽  
Author(s):  
B. Corman ◽  
N. Roinel
Keyword(s):  
Age Groups ◽  
Renal Hypertrophy ◽  
Sodium Potassium ◽  
Aging Rats ◽  
Age Related ◽  
Single Nephron Filtration Rate ◽  
Single Nephron ◽  
Old Rats ◽  
Low Incidence ◽  
Single Nephron Filtration Rates

Age-related changes in the function of individual nephrons were investigated by micropuncture experiments measuring single-nephron filtration rates (SNGFR) and proximal reabsorptions in 10-, 20-, and 30-mo-old rats. The animals were female WAG/Rij rats with low incidence of chronic progressive nephropathy, no loss of nephrons, and renal hypertrophy of both kidneys in the oldest animals. Mean SNGFR values per gram kidney weight were 41.4 +/- 1.1, 37.1 +/- 1.5, and 32.2 +/- 1.1 nl.min-1.g kidney wt-1 (n = 41) in the 10-, 20-, and 30-mo-old animals, respectively. This age-related decrease in filtration was no longer apparent when SNGFR values were expressed per nephron (means 24.3 +/- 0.7, 23.7 +/- 0.9, and 24.4 +/- 0.9 nl/min. Individual filtered loads of sodium, potassium, calcium, and magnesium and their absolute reabsorption by the proximal tubule were not different in the three age groups; however, absolute and fractional reabsorptions of phosphate decreased significantly in the 30-mo-old rats. These results indicate that, with the exception of phosphate, individual filtrations and proximal reabsorptions are well maintained in aging rats free of disease. This may be related to the observed renal hypertrophy.

Public Evaluation of Fish Tainting from Pulp and Paper Mill Discharges

1992 ◽  
Vol 25 (2) ◽  
pp. 57-64
Author(s):  
C. G. Jardine
Keyword(s):  
Yellow Perch ◽  
Action Plan ◽  
Pulp Mill ◽  
Paper Mill ◽  
Pulp And Paper ◽  
Salmo Gairdneri ◽  
Pulp And Paper Mill ◽  
Advisory Committees ◽  
Public Advisory ◽  
St Lawrence River

As part of the Remedial Action Plan (RAP) programs for the St. Lawrence and Spanish Rivers in Ontario, Canada, tainting evaluations were conducted using members of the Public Advisory Committees (PACs) and the RAP teams. Triangle test sensory evaluations were conducted on caged rainbow trout (Salmo gairdneri) exposed insitu upstream and downstream of the pulp and paper mill diffuser outfalls In the St. Lawrence River only, evaluations were conducted on indigenous yellow perch (Perca flavescens) caught upstream and downstream of the mill discharge . In both locations, the odour of the flesh from the caged trout exposed above the diffuser outfall was not judged significantly different from caged trout exposed downstream of the discharge. However, the indigenous perch caught downstream of the mill in the St. Lawrence River were judged by the panelists to have a significantly more objectionable odour than those caught upstream of the discharge. While the effluent tainting potential appears to have been eliminated in the Spanish River, further studies are required to determine the source and magnitude of tainting concerns in the St. Lawrence River. The sensory test and results reported here provide useful tools for evaluating the tainting potential of pulp mill discharges and for assessing perceived consumer quality of the fish exposed to these effluents.

Glomerular and tubular interactions between renal adrenergic activity and nitric oxide

1995 ◽  
Vol 268 (6) ◽  
pp. F1004-F1008 ◽  
Author(s):  
F. B. Gabbai ◽  
S. C. Thomson ◽  
O. Peterson ◽  
L. Wead ◽  
K. Malvey ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Glomerular Filtration ◽  
Renal Nerves ◽  
Ang Ii ◽  
Nitric Oxide Synthase Inhibitor ◽  
Adrenergic Activity ◽  
Single Nephron ◽  
Synthase Inhibitor ◽  
Oxide Synthase

Endothelium-dependent nitric oxide (EDNO) exerts control over the processes of glomerular filtration and tubular reabsorption. The importance of the renal nerves to the tonic influence of EDNO in the glomerular microcirculation and proximal tubule was tested by renal micropuncture in euvolemic adult male Munich-Wistar rats. The physical determinants of glomerular filtration and proximal reabsorption were assessed before and during administration of the nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (L-NMMA), in control animals and in animals 5–9 days after either ipsilateral surgical renal denervation (DNX) or after either sham surgery (SHX). L-NMMA caused single-nephron glomerular filtration rate to decline in control and SHX animals but not in DNX rats. L-NMMA caused a reduction in proximal reabsorption in control and SHX rats, which was prevented by prior DNX. DNX did not alter urinary guanosine 3',5'-cyclic monophosphate excretion, and, although DNX upregulates glomerular angiotensin II (ANG II) receptors, prior DNX did not alter intrarenal ANG II content as evaluated by radioimmunoassay. Some component of renal adrenergic activity is required for the full expression of the glomerular and tubular effects of blockade of nitric oxide synthase.

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