The Extraction Fraction of p-Aminohippurate in the Superficial and Deep Venous Drainage Area of the Cat Kidney

Nissen, Ole I.

doi:10.1111/j.1748-1716.1968.tb04111.x

Cited by 17 publications

(3 citation statements)

References 17 publications

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“…Still, however, the ischemic stress on the kidneys during the preparation manifested itself in a reduced capacity for PAH extraction. The extraction fractions for the superficial and deep venous blood were 0.85 and 0.61, respectively, as compared to 0.95 and 0.82 in previous experiments on kidneys in situ (14). This is in accordance with previous reports (15) that impairment of PAH transport capacity is a consequence of kidney ischemia.…”

Section: Discussionsupporting

confidence: 91%

Direct Measurement of Superficial and Deep Venous Flow in the Cat Kidney

Nissen

Galskov

1972

Circulation Research

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In an excised cat kidney, the subcapsular veins were clipped near their connections with the renal vein and cut open distal to the clamps. The kidney was then placed in an oil-filled lucite chamber and perfused from a donor cat via tubes entering the chamber through its close-fitting lid. The blood leaking from the cut subcapsular veins was led to one flowmeter; that leaving via the cannulated renal vein (supplied now only by the arcuate vein system) was led to another flowmeter. Catecholamines and stimulation of the renal nerves reduced the arcuate blood flow more than the subcapsular blood flow, the two average reductions being 28% and 20% with epinephrine and 22% and 14% with stimulation of the renal nerves. Angiotensin reduced both flows equally. Microspheres reduced the subcapsular flow more than the arcuate flow, the two average reductions being 42% and 25% of the control flows. This effect was probably caused by trapping of the microspheres in the distal ends of the interlobular arteries beyond the inlets to the afferent arterioles, since these vessels are too narrow to allow free entrance of the microspheres. The preferential effect of epinephrine and nerve stimulation on the deep circulation is thought to be the result of the special structure of the juxtamedullary glomerular units. • In the cat kidney, the veins draining the outer cortex are well separated from those draining the inner cortex and the medulla, because the blood from the outer cortex leaves through subcapsular veins which do not join the arcuate vein system until the hilar region (1, 2) (Fig. 1). In this paper, we will describe how the rates of blood flow leaving the subcapsular and the arcuate veins can be measured directly and simultaneously and show that the vessels in the two drainage areas react differently to certain external

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Section: Discussionsupporting

confidence: 91%

Direct Measurement of Superficial and Deep Venous Flow in the Cat Kidney

Nissen

Galskov

1972

Circulation Research

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“…The absence of correlation shown in figure 3 does not really exclude such an hypothesis. Several factors, including in hibition of cortical extraction and intrarenal blood flow redistribution could influence the Epahchanges in humans [15][16][17][18],soexplaining the lack of relationship in individual changes in net tubular reabsorption of sodium did not correlate with the respective changes in Epah ( fig.3), it is not possible to suggest a causal relationship between the decrease in sodium reabsorption and the decrease in Epah-Intrarenal infusion of prostaglandins has been shown to produce natriuresis and de creased Epah [19][20][21][22], In addition, saline in fusion in normotensive and hypertensive sub jects and/or in animals has been found to be associated with decreased Epah and increased release of prostaglandins by the kidney [23][24][25]. On the other hand, there is evidence that prostaglandins inhibit uptake of PAH by kid ney cortical slices in vitro [26].…”

Section: Discussionmentioning

confidence: 99%

Relationship between Glomerular Filtration Rate and Tubular Reabsorption of Sodium in Patients with Unilateral Renal Artery Stenosis.

Papanicolaou¹,

Mountokalakis²,

Safar³

et al. 1977

Nephron

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In patients with renovascular hypertension, a significant decrease in glomerular filtration rate (GFR) and in renal plasma flow (RPF) in the stenotic kidney was accompanied by a significant homolateral decrease in extraction of PAH (E_PAH) and in net tubular reabsorption of sodium (R_Na)· There was a highly significant correlation between differences in R_Na and differences in either GFR or RPF, while no correlation between differences in R_Na and in Epah was noted. It is suggested that the nature of the relationship between GFR and R_Na is essentially the same in unilateral renal artery stenosis in man, as in acute constriction of the renal artery or the aorta in the experimental animal.

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“…This disparity may result from the fact that PAH extraction is, at best, a poor indicator of distribution of blood flow, since it is not completely extracted from blood perfusing cortical nephrons at normal blood flow rates and the extraction by cortical nephrons is further decreased by ureteral occlusion (14).…”

Section: Discussionmentioning

confidence: 99%

Intrarenal Distribution of Blood Flow during Elevation of Ureteral Pressure in Dogs

Carlson

Sparks

1970

Circulation Research

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The ^Kr method was used to determine the effect of elevated ureteral pressure on total cortical and outer medullary nutrient renal blood flow of pentobarbital-anesthetized dogs. Increased ureteral pressure during mild saline diuresis resulted in increased total nutrient blood flow from 316 to 402 ml/100 g/min. Autoradiographs demonstrated that the increased blood flow is confined to the renal cortex and that juxtamedullary cortical and outer medullary flow is unchanged. Elevated ureteral pressure decreased total renal blood flow from 473 to 381 ml/g/min during copious mannitol diuresis. This is due at least partly to decreased cortical blood flow; we were unable to measure juxtamedullary cortical plus outer medullary blood flow during mannitol diuresis. Isolated renal arteries relaxed when placed in a physiologic salt solution containing 70 mM mannitol. Renin release is increased during elevation of ureteral pressure. We concluded that the mechanism for increased renal blood flow during ureteral occlusion selectively involves the nutrient circulation of the renal cortex.

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The Extraction Fraction of p-Aminohippurate in the Superficial and Deep Venous Drainage Area of the Cat Kidney

Cited by 17 publications

References 17 publications

Direct Measurement of Superficial and Deep Venous Flow in the Cat Kidney

Direct Measurement of Superficial and Deep Venous Flow in the Cat Kidney

Relationship between Glomerular Filtration Rate and Tubular Reabsorption of Sodium in Patients with Unilateral Renal Artery Stenosis.

Intrarenal Distribution of Blood Flow during Elevation of Ureteral Pressure in Dogs

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