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  • Atrium  (1)
  • Chloride  (1)
  • Kidney transplantation  (1)
  • 1
    ISSN: 1432-2013
    Schlagwort(e): Glomerular filtration rate ; Juxta-glomerular apparatus ; Macula densa ; Tubulo-glomerular feedback ; Chloride
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract It has been concluded that tubulo-glomerular feedback mechanism is triggered by changes in NaCl concentration ([NaCl]) at the macula densa. This conclusion is based on the demonstration that changes in filtration rate produced during retrograde perfusion of the loop of Henle depend upon the perfusate [NaCl]. Experiments were performed to evaluate whether the effect on glomerular function of orthograde perfusion of the loop of Henle is consistent with this conclusion. Early proximal flow rate ( $$\dot V_{EP} $$ ), stop-flow pressure (P SF), early distal chloride concentration ([Cl]), and flow rate were measured during perfusion of the loop of Henle with mannitol solution (300 mosm kg−1), 30 mM NaCl+mannitol (300 mosm kg−1), 140 mM Na isethionate and artificial tubular fluid. When distal flow exceeded 10 nl min−1, the magnitude of the glomerular response was predictable from the [Cl]. The linear regression line, $$\Delta \dot V_{EP} = - 0.027{\text{ }}[Cl]{\text{ + 4}}{\text{.3}}$$ , did not differ from that obtained previously with the retrograde technique. Retrograde perfusion with 140 mM Na isethionate was without effect on $$\dot V_{EP} $$ . We conclude that the effect on glomerular function of perfusion of the loop of Henle in either an orthograde or a retrograde direction with these solutions depends upon the chloride concentration at the macula densa.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 395 (1982), S. 271-276 
    ISSN: 1432-2013
    Schlagwort(e): Kidney ; Glomerular filtration rate ; Atrium ; NaCl excretion ; Volume regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Micropuncture studies of the renal effects of atrial natriuretic substance. Injection of atrial extract produced by homogenization, boiling and centrifugation of atrial tissue from one heart caused a 10 fold increase in urine flow rate and a 30-fold increase in Na excretion. Similarly prepared extracts of ventricle were without effect. To identify the site of action of atrial natriuretic substance, extract was infused intravenously at rates corresponding to 3 or 6 atria per hour. During infusion at a rate of 3 atria per hour mean urine flow increased from 9.5±2.8 to 17.2±1.2 μl/min and Na excretion from 0.14±0.06 to 1.78±0.14 μmol/min. Glomerular filtration rate (GFR), single nephron filtration rate (SNGFR) and proximal and loop of Henle fluid absorption did not change significantly. During infusion of 6 atria per hour, paralleling a greater rise in urine flow rate (from 6.4±2.09 to 40.3±7.5 μl/min) and in sodium excretion (from 0.18±0.0008 to 5.97±0.93 μmol/min), filtration rate, measured for either the single nephron or the whole kidney, rose. As a consequence of the rise in GFR, delivery of fluid and chloride into the distal tubule increased significantly. These data suggest that to a major extent the natriuresis is caused by transport inhibition along collecting tubules and collecting ducts. In addition, at high doses a rise in filtration rate contributes to the natriuretic effect of atrial extracts.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1432-2013
    Schlagwort(e): Prague hypertensive rat ; Kidney and hypertension ; Genetic hypertension ; Hypertensive substance ; Kidney transplantation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract It has been shown that genetic hypertension in rats usually “travels with the kidney”. To elucidate the mechanism of this phenomenon further, experiments were carried out in the Prague hypertensive (PH) rat, a model of genetic hypertension derived from the Wistar strain, in which a normotensive parallel, the Prague normotensive (PN) rat, was also bred from the same parent pair. Thus, it is possible to transfer organs between both parallels without substantial signs of rejection and without the use of immunosuppressive drugs. Unilateral nephrectomy and transplantation of one kidney between PH and PN rats, did not affect the arterial blood pressure (BP). Transplantation of one kidney from PN rats to bilaterally nephrectomised PH rats normalised the high BP. If a PH rat was left with one original kidney in situ after the transplantation of a “normotensive” kidney, the high BP persisted until the original “hypertensive” kidney was removed. This removal resulted in sustained normalisation of BP. When the development of high BP in the PH rats was prevented for 2 months after weaning by antihypertensive drugs, transplantation of kidneys from these rats to bilaterally nephrectomised PN rats always induced a sustained hypertension in the recipient. These results argue against a role of high-BP-induced damage to the kidney and against an intrinsic increase in the salt-reabsorptive capacity of the tubular epithelium in PH rats. The data support the view that the kidney from PH rats produces a “hypertensinogenic” substance, the secretion of which is genetically determined and is not influenced by the magnitude of the BP.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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