Effect of Diuretics on Sodium and Chloride Permeability in the Rat Papillary Collecting Duct

1998 ◽  
Vol 24 (5) ◽  
pp. 321-325
Author(s):  
Cheryl Ray ◽  
Shane Carney ◽  
Allistair Gillies
Keyword(s):  
Collecting Duct ◽  
Chloride Permeability ◽  
Papillary Collecting Duct

Urodilatin: binding properties and stimulation of cGMP generation in rat kidney cells

1993 ◽  
Vol 264 (2) ◽  
pp. F267-F273
Author(s):  
H. Saxenhofer ◽  
W. R. Fitzgibbon ◽  
R. V. Paul
Keyword(s):  
Guanylate Cyclase ◽  
Mesangial Cells ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Binding Characteristics ◽  
Papillary Collecting Duct ◽  
Collecting Duct Cells ◽  
Medullary Collecting Duct ◽  
Anp Receptors

Urodilatin (URO) [ANP-(95-126)] is an analogue of atrial natriuretic peptide (alpha-ANP) [ANP-(99-126)] that was first isolated from human urine. In rat mesangial cells, URO competed with high affinity for non-guanylate cyclase-coupled ANPR-C receptors [concentration at which 50% labeled ligand is displaced (IC50) approximately 70 pM], but with lesser affinity to the guanylate cyclase-linked ANPR-A receptors (IC50 approximately 800 pM). alpha-ANP bound to both receptors with similar affinity [dissociation constant (Kd) approximately 150 pM]. In papillary collecting duct homogenates, which possess only ANPR-A receptors, the apparent Kd value averaged 229 pM for alpha-ANP and 2.7 nM for URO. Intravenous URO was at least as potent and effective as alpha-ANP in inducing diuresis and natriuresis in anesthetized rats, but URO was approximately 10-fold less potent in stimulating guanosine 3',5'-cyclic monophosphate generation in mesangial and inner medullary collecting duct cells. We conclude that URO has a lesser affinity than alpha-ANP for guanylate cyclase-coupled ANP receptors in the kidney and that the relative natriuretic potency of URO in vivo cannot be directly attributed to its binding characteristics with ANPR-A receptors.

Micropuncture study of the effect of ANP on the papillary collecting duct in the rat

1988 ◽  
Vol 254 (4) ◽  
pp. F477-F483 ◽  
Author(s):  
A. van de Stolpe ◽  
R. L. Jamison
Keyword(s):  
Collecting Duct ◽  
Sodium Concentration ◽  
Sodium Reabsorption ◽  
Micropuncture Study ◽  
Papillary Collecting Duct ◽  
Group 3 ◽  
Group 2 ◽  
Tubule Fluid ◽  
Group 1

Micropuncture collections were obtained from the terminal collecting duct (CD) at base and tip of the renal papilla of the rat. Group 1 was studied before and during infusion with atrial natriuretic peptide (ANP), group 2 was administered the vehicle only, and group 3 received acetazolamide to increase sodium delivery to the base to a similar extent as after ANP. ANP caused a decrease in blood pressure, a slight increase in GFR, natriuresis, and diuresis. Sodium delivery to the collecting duct at the base of the papilla increased. Between base and tip, sodium reabsorption was inhibited. Tubule fluid sodium concentration (TFNa) was increased at the base and remained high at the tip; in contrast TFNa fell between base and tip in control and acetazolamide groups. After acetazolamide, sodium reabsorption in the terminal CD was not inhibited. These results demonstrate that in vivo ANP 1) increases the delivery of sodium to the terminal CD and 2) inhibits sodium reabsorption in the terminal CD. The findings for chloride were similar to those for sodium. ANP also increased delivery of H2O, K, Ca, and Mg to the CD at the papillary base but did not significantly affect their transport by the terminal CD.

Water reabsorption by papillary collecting ducts in the remnant kidney

1982 ◽  
Vol 242 (6) ◽  
pp. F657-F663
Author(s):  
J. P. Pennell ◽  
J. J. Bourgoignie
Keyword(s):  
Collecting Duct ◽  
Sham Operation ◽  
Water Delivery ◽  
Water Reabsorption ◽  
Urinary Osmolality ◽  
Load Dependence ◽  
Physiological Processes ◽  
Collecting Ducts ◽  
Papillary Collecting Duct ◽  
Remnant Kidney

Water transport by terminal papillary collecting ducts was examined by micropuncture of the renal papilla in 15 rats with a solitary remnant kidney (RK) and in 27 normal rats, 10 of which had undergone sham operation. Before papillary exposure, urinary osmolality was significantly (P less than 0.001) lower in RK rats (685 vs. 1,722 mosmol/kg H2O in normal rats). After papillary exposure, urinary osmolality decreased by 50% in normal rats but did not change in RK rats. In RK rats, a greater percentage of filtered water was delivered to (5.74% vs. 2.29% in normal rats, P less than 0.001) and reabsorbed by (1.94% vs. 0.94% in normal rats, P less than 0.005) the terminal millimeter of papillary collecting ducts. Fractional water reabsorption by terminal papillary collecting ducts correlated directly (r = 0.83, P less than 0.001) with fractional water delivery, suggesting load dependence of water reabsorption. Estimated absolute water reabsorption by terminal collecting ducts was equivalent for remnant and normal kidneys and increased two-to fourfold in remnant kidneys when analyzed per functioning papillary collecting duct. There was an inverse relationship between urinary osmolality and fractional water delivery to papillary collecting ducts (r = 0.65, P less than 0.001). Although the data do not exclude functional alterations of papillary collecting ducts, the events underlying the reduction of urinary osmolality in remnant kidneys appear to involve physiological processes based on a high delivery and reabsorption of water.

Effects of aldosterone on potassium recycling in the kidney of adrenalectomized rats

1985 ◽  
Vol 248 (2) ◽  
pp. F219-F227 ◽  
Author(s):  
E. Higashihara ◽  
J. P. Kokko
Keyword(s):  
Wistar Rats ◽  
Collecting Duct ◽  
Distal Tubule ◽  
Feedback System ◽  
Blood Levels ◽  
Segmental Analysis ◽  
Urinary Potassium ◽  
Papillary Collecting Duct ◽  
Potassium Secretion ◽  
Potassium Recycling

Recent studies have suggested that potassium, like urea, undergoes medullary recycling. The present cortical and papillary micropuncture studies were designed to confirm the existence of medullary potassium recycling and to determine whether acute infusions of aldosterone affected this phenomenon. Thus, nephron segmental analysis of potassium and sodium transport was conducted in adrenalectomized Munich-Wistar rats and similarly prepared rats that received aldosterone acutely to achieve physiological blood levels. The clearance results demonstrated that aldosterone has an acute antinatriuretic and a kaliuretic effect, whereas the micropuncture studies demonstrated that 1) aldosterone increases potassium secretion between early and late distal tubule punctures; 2) aldosterone causes an increase in delivery of potassium to the papillary collecting duct; 3) aldosterone does not increase potassium secretion across the papillary collecting duct; and 4) aldosterone significantly increases medullary potassium recycling as evidenced by increased quantities of potassium present at the bend of the loop of Henle in response to aldosterone infusions. Thus, the studies confirm the existence of potassium recycling and suggest that this phenomenon is a feedback system that, in part, regulates urinary potassium excretion.

scholarly journals A Na-K-Cl cotransporter in isolated rat papillary collecting duct cells

1989 ◽  
Vol 36 (2) ◽  
pp. 201-209 ◽  
Author(s):  
Clemens Grupp ◽  
Iris Pavenstädt-Grupp ◽  
R. Willi Grunewald ◽  
Christopher Bevan ◽  
John B. Stokes ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Duct Cells ◽  
Papillary Collecting Duct ◽  
Collecting Duct Cells ◽  
Isolated Rat

Bradykinin modulates focal adhesions and induces stress fiber remodeling in renal papillary collecting duct cells

2008 ◽  
Vol 294 (3) ◽  
pp. F603-F613 ◽  
Author(s):  
María Gabriela Márquez ◽  
María del Carmen Fernández-Tome ◽  
Nicolás Octavio Favale ◽  
Lucila Gisele Pescio ◽  
Norma Beatriz Sterin-Speziale
Keyword(s):  
Cultured Cells ◽  
Cell Attachment ◽  
Average Length ◽  
Collecting Duct ◽  
Focal Adhesions ◽  
Axial Ratio ◽  
Cytoskeleton Organization ◽  
Duct Cells ◽  
Papillary Collecting Duct ◽  
Collecting Duct Cells

Focal adhesions (FAs) are specialized regions of cell attachment to the extracellular matrix. Previous works have suggested that bradykinin (BK) can modulate cell-matrix interaction. In the present study, we used a physiological cellular model to evaluate the potential role of BK in modulating FAs and stress fibers. We performed a quantitative morphometric analysis of FAs in primary cultured rat renal papillary collecting duct cells, which included size, axial ratio (shape), and average length. After 1, 5, or 10 min of incubation with BK, cultured cells were immunostained and analyzed by confocal microscopy. Although the shape of FAs was not altered, BK induced a decrease in the number of vinculin-stained FAs per cell, and a decrease in both their size and their average length, but not in talin-containing FAs, thus suggesting that BK could be inducing a restructuring of FAs. BK also induced a remodeling of the actin filament assemblies rather than their dissipation. Since we have previously demonstrated that BK stimulates activation of PLCβ in rat renal papillae, we attempted to determine whether BK can modulate FA restructuring by this mechanism, by pretreating cultured cells with the PLCβ inhibitor U73122. The present study, performed under physiological conditions with cells that were not genetically manipulated, provides new experimental evidence supporting the notion that the intrarenal hormone BK modulates FAs and actin cytoskeleton organization through a mechanism that involves the activation of PLCβ. We propose this finding as a novel mechanism for BK modulation of tubular collecting duct function.

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