Blood Flow in the Renal Medulla

Lilienfield, Lawrence S.; Maganzini, Herman C.; Bauer, Mark H.

doi:10.1161/01.res.9.3.614

Cited by 64 publications

(16 citation statements)

References 4 publications

(3 reference statements)

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“…The order in which the two drugs were given was alternated from study to study. Renal (8). An infusion of '251-albumin (Mallinckrodt, Inc., Maryland Heights, Mo.)…”

Section: Methodsmentioning

confidence: 99%

Studies on the Mechanism of Sodium Excretion during Drug-induced Vasodilatation in the Dog

Fadem¹,

Hernandez-Llamas²,

Patak³

et al. 1982

J. Clin. Invest.

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A B S T R A C T The administration of vasodilating agents such as bradykinin and acetylcholine cause an increase in urinary sodium excretion. Yet the mechanisms involved in this natriuretic effect are not clear. Recent studies with another renal vasodilator, secretin have shown this drug also causes a profound increase in renal blood flow but without major changes in sodium excretion. To attempt to delineate the basis of this difference in sodium excretion with these drugs, the renal functional effects of secretin and bradykinin were compared at an equivalent vasodilating dose. Bradykinin increased renal blood flow from 222 to 342 ml/min, urine volume from 0.2 to 1.2 ml/min, and urine sodium excretion from 28 to 115,ueq/min. Urine osmolality fell from 1,230 to 401 mosmol/kg. Secretin caused a comparable increase in renal blood flow (216 to 325 ml/min) while changes in urine flow, sodium excretion, and urine osmolality were significantly less.In further studies papillary plasma flow was estimated using the albumin accumulation technique. Control papillary plasma flow was 29 ml/min per 100 g. Bradykinin increased urinary sodium excretion 108 seq/min and decreased urinary osmolality from 1,254 to 516 mosmol/kg in association with a rise in papillary plasma flow to 62 ml/min per 100 g. Urine sodium excretion, urinary osmolality, and urine flow rate, as well as papillary plasma flow rate (32 ml/min per 100 g) were unchanged from control when secretin was administered. Studies with acetylcholine were qualitatively similar to those of bradykinin. Renal blood flow increased from 150 to 248 ml/min, urinary sodium excretion increased from 20 to 243 geq/min, urinary osmolality decreased from 1,237 to 411 mos-

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“…The order in which the two drugs were given was alternated from study to study. Renal (8). An infusion of '251-albumin (Mallinckrodt, Inc., Maryland Heights, Mo.)…”

Section: Methodsmentioning

confidence: 99%

Studies on the Mechanism of Sodium Excretion during Drug-induced Vasodilatation in the Dog

Fadem¹,

Hernandez-Llamas²,

Patak³

et al. 1982

J. Clin. Invest.

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“…Papillary plasma flow (PPF) was determined by a modification of the original method of Lilienfield et al (1961). The technique has been described previously in detail (Lameire et al, 1978).…”

Section: Papillary Plasma Flow Measurementsmentioning

confidence: 99%

Role of medullary hemodynamics in the natriuresis of drug-induced renal vasodilation in the rat.

Lameire¹,

Vanholder²,

Ringoir³

et al. 1980

Circulation Research

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(1971) /iEq/min, respectively; P < 0.05). PPF rose from 50 ± 2.6 ml/min 100 g (mean ± SE) in control rats to 91 ± 4.7 ml/min 100 g after ACh (p < 0.001). Despite a similar increase in PAH clearance after secretin (+ 2.21 ml/min; P< 0.01), U N ,V remained unchanged and PPF was only slightly, although significantly, increased (from 50 ± 2.6 ml/min 100 g to 65 ± 2.75 ml/min 100 g; P < 0.05). Both total kidney and papillary vasodilation, and the increase in U Na V after ACh were blocked by previous administration of meclofenamate (M), a prostaglandin inhibitor. No effect of M in secretin-infused rats was observed. In conclusion, the relationship between total renal vasodilation and natriuresis was dissociated with secretin, but not with ACh. However, a relationship between the natriuresis and influence on papillary hemodynamics was observed with both vasodilators. Finally, the renal hemodynamic and natriuretic effects of ACh are probably mediated by prostaglandin release. Circ Res 47: 839-844, 1980

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“…is a modification of the albumin accumulation technique originally described by Lilienfield and colleagues (5 At the time of PPF measurement, an infusion of 125j albumin (approximately 15 ,uCi/ml, Mallinckrodt Inc., St. Louis, Mo.) and 7% FDC green dye was begun at a rate of 0.45 ml/min via the jugular vein.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, we designed the majority of studies in such a way that the primary technical problem of the method would be obviated. It is apparent from the previous studies in both dog and rat that there is a significant variation in the absolute plasma flow measurement in a given experimental model (5,6,8). This presumably relates to both methodologic considerations and animal variation.…”

Section: Introductionmentioning

confidence: 99%

Studies on the Mechanism of Reduced Urinary Osmolality after Exposure of the Renal Papilla

Chuang¹,

Reineck²,

Osgood³

et al. 1978

J. Clin. Invest.

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A B S T R A C T Studies were performiied in MlunichWistar rats to determine whether chaniges in papillary plasma flow might be responsible for the conicentrating defect which occurs after exposure of the extrarenal papilla. Papillary plasma flow was measured by 1251_ albumin accutnmulation. Initial studies in hydropenic animals revealed that papillary plasma flow was 40% higher in the kidney with the exposured papilla, 41 vs. 29 ml/min per 100 g of papilla (P < 0.001). This increase in papillary plasma flow was detectable 15 or 45 min after renmoving the ureter. Because it was unclear whether the rise in papillary plasnma flow was a cause or the result of the fall in urine osmolality, similar studies were performed in animals undergoing a water diuresis. In this setting, papillary plasma flow still increased on the exposed side compared to the control side, 81 vs. 60 ml/min per 100 g, despite similarly low uirine osmolalities of 155 and 174 mosmol/kg, respectively. This finding is compatible with the possibility that papillary exposure per se causes an increase in papillary plasma flow and that this hemodynamic alteration may lead to a reduction in urinary osmolality secondary to washout of the medullary interstitium. A final group of hydropenic rats was given either indomethacin or meclofenamate before removing the ureter. In these studies, there was no difference in either the papillary plasma flow or the urine osmolality between control and exposed kidneys. It is therefore suggested that opening the ureter induces an increase in papillary plasma flow by some mechanism which may involve an alteration in prostaglandiin synthesis.

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Blood Flow in the Renal Medulla

Cited by 64 publications

References 4 publications

Studies on the Mechanism of Sodium Excretion during Drug-induced Vasodilatation in the Dog

Studies on the Mechanism of Sodium Excretion during Drug-induced Vasodilatation in the Dog

Role of medullary hemodynamics in the natriuresis of drug-induced renal vasodilation in the rat.

Studies on the Mechanism of Reduced Urinary Osmolality after Exposure of the Renal Papilla

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