COMPARATIVE ASSESSMENT OF ULTRASOUND INDICATORS OF INTRARENAL BLOOD FLOW IN THE EARLY DIAGNOSIS OF RENAL LESIONS

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.

Download Full-text

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.

Download Full-text

Measurement of Intrarenal Blood Flow Distribution

Renal Pharmacology ◽

10.1007/978-1-4615-8894-8_3 ◽

1978 ◽

pp. 41-74 ◽

Cited By ~ 2

Author(s):

Norbert H. Lameire ◽

Elaine L. Chuang ◽

Richard W. Osgood ◽

Jay H. Stein

Keyword(s):

Blood Flow ◽

Flow Distribution ◽

Blood Flow Distribution ◽

Intrarenal Blood Flow

Download Full-text

Angiotensin II and nitric oxide in neural control of intrarenal blood flow

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00477.2004 ◽

2005 ◽

Vol 289 (3) ◽

pp. R745-R754 ◽

Cited By ~ 16

Author(s):

Niwanthi W. Rajapakse ◽

Amanda K. Sampson ◽

Gabriela A. Eppel ◽

Roger G. Evans

Keyword(s):

Nitric Oxide ◽

Blood Flow ◽

Angiotensin Ii ◽

Nitric Oxide Synthase ◽

Neural Control ◽

Renin Angiotensin System ◽

Renal Medulla ◽

Renal Nerve ◽

Intrarenal Blood Flow ◽

Oxide Synthase

We investigated the roles of the renin-angiotensin system and the significance of interactions between angiotensin II and nitric oxide, in responses of regional kidney perfusion to electrical renal nerve stimulation (RNS) in pentobarbital sodium-anesthetized rabbits. Under control conditions, RNS (0.5–8 Hz) reduced total renal blood flow (RBF; −89 ± 3% at 8 Hz) and cortical perfusion (CBF; −90 ± 2% at 8 Hz) more than medullary perfusion (MBF; −55 ± 5% at 8 Hz). Angiotensin II type 1 (AT1)-receptor antagonism (candesartan) blunted RNS-induced reductions in RBF ( P = 0.03), CBF ( P = 0.007), and MBF ( P = 0.04), particularly at 4 and 8 Hz. Nitric oxide synthase inhibition with NG-nitro-l-arginine (l-NNA) enhanced RBF ( P = 0.003), CBF ( P = 0.001), and MBF ( P = 0.03) responses to RNS, particularly at frequencies of 2 Hz and less. After candesartan pretreatment, l-NNA significantly enhanced RNS-induced reductions in RBF ( P = 0.04) and CBF ( P = 0.007) but not MBF ( P = 0.66). Renal arterial infusion of angiotensin II (5 ng·kg−1·min−1) selectively enhanced responses of MBF to RNS in l-NNA-pretreated but not in vehicle-pretreated rabbits. In contrast, greater doses of angiotensin II (5–15 ng·kg−1·min−1) blunted responses of MBF to RNS in rabbits with intact nitric oxide synthase. These results suggest that endogenous angiotensin II enhances, whereas nitric oxide blunts, neurally mediated vasoconstriction in the renal cortical and medullary circulations. In the renal medulla, but not the cortex, angiotensin II also appears to be able to blunt neurally mediated vasoconstriction.

Download Full-text