Intrarenal blood flow distribution in dog kidney determined by 99mTc microaggregates and 201Tl

Intrarenal distribution of blood flow was assessed with radioactive albumin microaggregates (MA) in three cortical zones of the dog kidney. The experimentally obtained zonal fractions of total renal blood flow were compared with predicted zonal blood flow fractions obtained in a mathematical model. The maximal degree of skimming that could possibly occur in a single experiment was estimated. The analysis showed that local blood flow in the inner cortical zone was maximally underestimated by 17% because of skimming of MA, and in the outer cortical zone the blood flow was maximally overestimated by 13% with the method of radioactive MA uptake. Renal uptake of 201Tl was measured simultaneously in exactly the same locations. Paired measurements of intrarenal blood flow distribution by MA and Tl uptake methodologies showed that local blood flow assessed with MA in the inner cortical zone was significantly lower than that obtained with 201Tl and that a higher blood flow rate was obtained in the outer cortical zone with MA compared with 201Tl. This disparity could be accounted for by the effect of skimming of MA as predicted by the model.

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The Effect of Furosemide on the Intrarenal Blood Flow Distribution in the Dog

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y72-113 ◽

1972 ◽

Vol 50 (8) ◽

pp. 774-783 ◽

Cited By ~ 4

Author(s):

Serge Carrière ◽

Michel Desrosiers ◽

Jacques Friborg ◽

Michèle Gagnan Brunette

Keyword(s):

Blood Flow ◽

Flow Rate ◽

Urine Volume ◽

Flow Distribution ◽

Blood Flow Rate ◽

Initial Distribution ◽

Blood Flow Distribution ◽

Intrarenal Blood Flow ◽

Femoral Blood ◽

Furosemide Administration

Furosemide (40 μg/min) was perfused directly into the renal artery of dogs in whom the femoral blood pressure was reduced (80 mm Hg) by aortic clamping above the renal arteries. This maneuver, which does not influence the intrarenal blood flow distribution, produced significant decreases of the urine volume, natriuresis, Ccreat, and CPAH, and prevented the marked diuresis normally produced by furosemide. Therefore the chances that systemic physiological changes occurred, secondary to large fluid movements, were minimized. In those conditions, however, furosemide produced a significant increase of the urine output and sodium excretion in the experimental kidney whereas Ccreat and CPAH were not affected. The outer cortical blood flow rate (ml/100 g-min) was modified neither by aortic constriction (562 ± 68 versus 569 ± 83) nor by the subsequent administration of furosemide (424 ± 70). The blood flow rate of the outer medulla in these three conditions remained unchanged (147 ± 52 versus 171 ± 44 versus 159 ± 54). The initial distribution of the radioactivity in each compartment remained comparable in the three conditions. In parallel with the results from the krypton-85 disappearance curves, the autoradiograms, silicone rubber casts, and EPAH did not suggest any change in the renal blood flow distribution secondary to furosemide administration.

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Skimming of microspheres in vitro: implications for measurement of intrarenal blood flow

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1981.241.3.h342 ◽

1981 ◽

Vol 241 (3) ◽

pp. H342-H347 ◽

Cited By ~ 3

Author(s):

E. S. Ofjord ◽

G. Clausen ◽

K. Aukland

Keyword(s):

Blood Flow ◽

Flow Distribution ◽

Blood Flow Distribution ◽

Particle Inertia ◽

Local Flow ◽

Size Dependent ◽

Dog Kidney ◽

Intrarenal Blood Flow ◽

Renal Cortical Blood Flow

Skimming could result in erroneous estimation of renal cortical blood flow distribution as measured by microspheres. Skimming of microspheres with diameters 10, 12, and 15 micrometers and red blood cells was therefore studied in a model in which an interlobular artery and its first arteriolar branch were simulated by 80- and 30-micrometers-wide slits between glass prisms. The experiments were performed with citrated blood at a hematocrit (Hct) of 40, flow velocities of 3 and 6 cm/s, and branch flow varying from 2 to 25%. At a branch flow fraction comparable to that of a deep arteriole in the dog kidney (3%), Hct in branch blood was 24% lower than that of input blood, whereas 10-, 12-, and 15-micrometers microsphere concentrations were 75, 81, and 87% lower, respectively. The size-dependent skimming was probably caused by wall exclusion in the main channel. Differences in particle inertia did not affect skimming. The results suggest that the disparate local flow values obtained by use of microspheres of different sizes in dog and rat kidneys are due to a size-dependent skimming of the microspheres.

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Intrarenal blood flow distribution during adenosine-mediated vasoconstriction

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1983.244.1.h138 ◽

1983 ◽

Vol 244 (1) ◽

pp. H138-H141 ◽

Cited By ~ 3

Author(s):

J. F. Macias ◽

M. Fiksen-Olsen ◽

J. C. Romero ◽

F. G. Knox

Keyword(s):

Blood Flow ◽

Renal Blood Flow ◽

Late Phase ◽

Flow Distribution ◽

Adenosine Infusion ◽

Blood Flow Distribution ◽

Intrarenal Blood Flow ◽

Renal Blood Flow Distribution ◽

Uniform Reduction ◽

Intrarenal Distribution

Intrarenal infusion of adenosine induces an initial vasoconstriction followed by a subsequent vasodilation. The intrarenal distribution of blood flow in the vasoconstriction phase is unknown. The present study was undertaken to assess the effect of intrarenal infusion of adenosine on intracortical distribution of renal blood flow during both the vasoconstriction and vasodilation phases. Renal blood flow distribution was measured with radiolabeled microspheres in anesthetized sodium-depleted dogs before and during the early vasoconstriction phase and the late vasodilation phase of intrarenal infusion of adenosine. During the vasoconstriction phase, there was a uniform decrease in blood flow in each renal cortical zone. In the late phase of adenosine infusion, there was a significant increase in deep cortical flow without significant changes in superficial cortical flow compared with control. The effects of adenosine were also compared with those exerted by norepinephrine in which decreased blood flow was demonstrated in all zones. We conclude that the vasoconstrictor phase of adenosine infusion is characterized by a uniform reduction of renal blood flow to all cortical zones, whereas the vasodilator phase is characterized by a selective deep cortical vasodilation.

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