Measurement of Intrarenal Blood-Flow Distribution in the Rabbit Using Radioactive Microspheres

1975 ◽  
Vol 48 (1) ◽  
pp. 51-60 ◽  
Author(s):  
D. J. Warren ◽  
J. G. G. Ledingham
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Renal Cortex ◽  
Flow Distribution ◽  
Rabbit Kidney ◽  
Radioactive Microspheres ◽  
Injection Dose ◽  
Intrarenal Blood Flow ◽  
Total Renal Blood Flow

1. Total renal blood flow and its distribution within the renal cortex of the conscious rabbit were studied with radioactive microspheres of 15 and 25 μm diameter. 2. The reliability of the microsphere technique was influenced by microsphere diameter and number (dose). The optimum microsphere diameter for determination of flow distribution in the rabbit kidney was 15 μm and dose 100–150 000 spheres. 3. Spheres of 15 μm nominal diameter were randomly distributed within the renal cortex of adult rabbits. The larger spheres in batches nominally 15 μm in diameter in young rabbits and 25 μm diameter in adult rabbits were preferentially distributed to the superficial cortex. 4. In adult rabbits 15 μm diameter spheres lodged in glomerular capillaries. Larger spheres occasionally lodged in interlobular arteries causing intrarenal haemorrhage. 5. Microspheres of 15 μm caused a decrease in renal clearance of creatinine and of p-aminohippurate when the total injection dose was about 200 000 spheres. These effects were greater when the injection dose was increased to 500 000 spheres. 6. The reduction in total renal blood flow observed with large doses of spheres largely reflected decreased outer cortical flow, as measured by a second injection of spheres, and confirmed by a decrease in p-aminohippurate extraction. 7. The reproducibility of multiple injection studies was limited by these intrarenal effects of microspheres. 8. Total renal blood flow measured in six rabbits in acute experiments by the microsphere technique was 107 ± 12 (mean±sd) ml/min and by p-aminohippurate clearance was 100 ± 10 ml/min. 9. Total renal blood flow in twelve conscious, chronically instrumented rabbits was 125 ± 11 ml/min, of which 92 ± 6 ml/min was distributed to the superficial cortex and 33 ± 4 ml/min to the deep cortex.

Effect of inhibition of peptidase activity on distribution of intrarenal blood flow

1975 ◽  
Vol 228 (3) ◽  
pp. 850-853 ◽  
Author(s):  
MD Bailie ◽  
JA Barbour
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Filtration Rate ◽  
Flow Distribution ◽  
Blood Flow Distribution ◽  
Angiotensin I ◽  
Intrarenal Blood Flow ◽  
Total Renal Blood Flow

Experiments were performed in dogs to determine the effects of the intravenous administration of the dipeptide hydrolase inhibitor SQ 20,881 on renal hemodynamics, intrarenal blood flow distribution, and renal function. Dipeptide hydrolase converts angiotensin I to angiotensin II and inactivates bradykinin. SQ 20,881 causes an inhibition of the vasoconstrictor response after angiotensin I and potentiation of the vasodilatory activity of bradykinin. Total renal blood flow, cortical distribution of blood flow, and glomerular filtration rate were determined. In seven animals administration of SQ 20,881 (1 mg/kg) resulted in a decrease in mean systemic blood pressure of 11 mmHg, an increase in total renal blood flow of 0.71 ml/min per g, and a significant fall in glomerular filtration rate. Fractional blood flow to the superficial cortex decreased and to the juxtamedullary cortex increased. Absolute flow was unchanged in the superficial cortex and increased significantly in the deep cortex. The findings are compatible with reported effects of bradykinin on intrarenal blood flow distribution, although the experiments do not distinguish between potentiation of bradykinin or inhibition of angiotensin I conversion.

Influence of Cortical Plasma Transit-Time on p-Aminohippurate Extraction during Induced Renal Vasodilatation in Anaesthetized Dogs

1972 ◽  
Vol 43 (3) ◽  
pp. 401-411 ◽  
Author(s):  
M. T. Velasquez ◽  
A. V. Notargiacomo ◽  
J. N. Cohn
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Transit Time ◽  
Prostaglandin E1 ◽  
Renal Cortex ◽  
Flow Distribution ◽  
Blood Flow Distribution ◽  
Pooled Data ◽  
Intrarenal Blood Flow ◽  
High Degree

1. The influence of intrarenal blood-flow distribution and plasma transit-time through the renal cortex on the reduction in p-aminohippurate (PAH) extraction (EPAH) induced by renal vasodilator agents was evaluated in anaesthetized dogs by an indicator-dilution technique. 2. Increases in renal blood flow during graded intravenous iso-osmotic saline or hyperosmotic mannitol infusions and during renal arterial infusions of acetylcholine or prostaglandin E1 were consistently associated with reduced EPAH. 3. The cortical fraction of renal blood-flow increased during vasodilatation induced by saline or acetylcholine but was unchanged during mannitol or prostaglandin infusions. Cortical blood volume (CBV) increased with saline infusion but was reduced with mannitol. Changes in CBV with acetylcholine and prostaglandin E1 were insignificant. No correlation could be found between changes in EPAH and changes in intrarenal blood flow distribution. 4. A high degree of correlation (r = 0·81) was noted between EPAH and the simultaneously determined mean cortical plasma transit-time. A significant correlation existed with pooled data for all infusions as well as with individual drug infusions. 5. We interpret these data to indicate that a shortened transit-time of plasma through the cortex, indicative of an increased velocity of cortical plasma flow, is the most important determinant of the lowering of EPAH during renal vasodilatation.

Renal Vascular Response to Haemorrhage in the Rabbit after Pentobarbitone, Chloralose–Urethane and Ether Anaesthesia

1978 ◽  
Vol 54 (5) ◽  
pp. 489-494
Author(s):  
D. J. Warren ◽  
J. G. G. Ledingham
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Renal Cortex ◽  
Ether Anaesthesia ◽  
Before And After ◽  
Conscious Rabbits ◽  
Urethane Anaesthesia ◽  
Renal Vascular ◽  
Cortical Distribution ◽  
Total Renal Blood Flow

1. Total renal blood flow and its cortical distribution were measured by the microsphere technique before and after haemorrhage in conscious rabbits, and after haemorrhage in rabbits anaesthetized with pentobarbitone, chloralose—urethane or ether. 2. The average blood loss necessary to achieve a fall in systolic blood pressure to about 65 mmHg was 101 ml in conscious rabbits and 38, 90 and 118 ml in weight-matched groups of rabbits anaesthetized with pentobarbitone, chloralose—urethane and ether respectively. 3. After haemorrhage in conscious rabbits total renal blood flow fell by 25%, this fall being confined to the superficial renal cortex. 4. In rabbits subject to haemorrhage under pentobarbitone anaesthesia renal blood flow fell by a further 23% when compared with the conscious bled rabbits. This reduction in blood flow was confined to the superficial cortex. 5. Haemorrhage in the rabbits subjected to chloralose—urethane anaesthesia caused no significant change in renal blood flow, as compared with conscious bled rabbits. 6. Haemorrhage under ether anaesthesia was associated with a further 33% fall in total renal blood flow, as compared with conscious bled rabbits. This was associated with a fall of 32% and 34% in superficial and deep cortical blood flow respectively. 7. Animals subjected to general anaesthesia may be particularly susceptible to the renal haemodynamic effects of haemorrhage.

Renal intracortical blood flow during hemorrhage: role of adrenergic mechanisms

1975 ◽  
Vol 229 (1) ◽  
pp. 178-184 ◽  
Author(s):  
Hardaker WT ◽  
TC Graham ◽  
AS Wechsler
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Renal Denervation ◽  
Renal Nerves ◽  
Radioactive Microspheres ◽  
Adrenergic Mechanisms ◽  
Anesthetized Dogs ◽  
Intrarenal Blood Flow ◽  
Inner Cortex

Hemorrhagic hypotensin in anesthetized dogs produced a redistribution of renal blood flow from the outer to the inner cortex. The role of adrenergic mechanisms in this redistribution was studied in anesthetized dogs using a radioactive microspheres to determine intrarenal blood flow. Neither renal denervation, nor pretreatment with reserpine altered the characteristic redistribution of renal cortical flow during hemorrhage. These observations suggest that neither intact renal nerves nor circulating catecholamines are necessary for the redistribution of renal intracortical blood flow during hemorrhagic hypotension, and the role of myogenic autoregulation is emphasized.

EFFECTS OF CHRONIC CYCLOSPORINE ADMINSTRATION ON RENAL BLOOD FLOW AND INTRARENAL BLOOD FLOW DISTRIBUTION

1991 ◽  
Vol 51 (2) ◽  
pp. 503-508 ◽  
Author(s):  
DEBBIE F. YOUNGELMAN ◽  
KIM U. KAHNG ◽  
BROOKE D. ROSEN ◽  
LISA S. DRESNER ◽  
RICHARD B. WAIT
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Flow Distribution ◽  
Blood Flow Distribution ◽  
Intrarenal Blood Flow

Sensitivity of the renal medullary circulation to plasma vasopressin

1996 ◽  
Vol 271 (3) ◽  
pp. R647-R653 ◽  
Author(s):  
K. G. Franchini ◽  
A. W. Cowley
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Intravenous Infusion ◽  
Control Level ◽  
Flow Distribution ◽  
Renal Medulla ◽  
Urine Osmolality ◽  
Water Restriction ◽  
Doppler Flowmetry ◽  
Total Renal Blood Flow

Studies were carried out to determine the effects of physiological changes of plasma arginine vasopressin (AVP) on blood flow distribution in the renal cortex and medulla. Acute decerebration was performed so that studies could be carried out within the low physiological range of circulating AVP. Changes of renal cortical and medullary microcirculatory blood flow were measured with implanted optical fibers and laser-Doppler flowmetry, and total renal blood flow was measured with transit-time ultrasonography. During intravenous infusion of increasing doses of AVP, when plasma AVP was increased in steps from 2.9 to 11.2 pg/ml by intravenous infusion, mean arterial pressure (98 +/- 3 mmHg), total renal blood flow (8.2 +/- 0.6 ml. min-1.g kidney-1), and blood flow in the microcirculation of the cortex (2.11 +/- 0.28 V) remained unchanged, whereas that in the renal medulla decreased progressively. Medullary flow was significantly reduced when circulating levels of AVP increased from a control level of 2.8 to 5.0 pg/ml. The reductions of medullary flow were accompanied by parallel increases of urine osmolality. These data indicate that the vessels supplying the renal medullary circulation are sensitive within the range of plasma AVP concentrations observed with moderate water restriction. The medullary circulation exhibits a sensitivity AVP that parallels that found in the medullary collecting ducts.

Neonatal changes in renal blood flow distribution in puppies

1975 ◽  
Vol 228 (5) ◽  
pp. 1453-1461 ◽  
Author(s):  
LC Aschinberg ◽  
DI Goldsmith ◽  
H Olbing ◽  
A Spitzer ◽  
Edelmann CM ◽  
...  
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Renal Cortex ◽  
Flow Distribution ◽  
Blood Flow Distribution ◽  
Outer Cortex ◽  
Outer Medulla ◽  
Inner Cortex ◽  
Renal Blood Flow Distribution ◽  
Intrarenal Distribution

The intrarenal distribution of blood flow was studied in 31 newborn mongrel puppies from 18 h to 70 days using xenon washout and krypton autoradiography. Mean renal blood flow increased from 0.39 plus or minus 0.05 ml/g per min (SE) the 1st wk to 2.06 plus or minus 0.12 ml/g per min at 6 wk. During the 1st wk of life renal cortex was perfused homo-geneously at 0.88 plus or minus 0.19 ml/g per min (SE) and accounted for 35 plus or minus 4% of the renal blood flow. During the 2nd wk a narrow, rapidly perfused zone of outer cortex was identified which was perfused at 3.35 plus or minus 0.26 ml/g per min, received 19.53 plus or minus 5.05% of the total renal blood flow, and represented 15 plus or minus 4% of the mass of the total cortex. The inner cortex and outer medulla at this time received 53.40 plus or minus 4.12% of the flow at 1.07 plus or minus 0.08 ml/g per min. Outer cortical flow increased with age reaching adult values by about 6-10 wk when the rapidly perfused area represented 40 plus or minus 8% of the cortex. These changes are parallel to the results of previously reported studies with microspheres in newborn puppies and are compatible with the well established maturational changes noted in neonates of several species. They represent the first gas-washout studies in animals during the first 6 wk of life.

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