scholarly journals Hormonal regulation of phospholipase D activity in Ca2+ transporting cells of rabbit connecting tubule and cortical collecting duct

2001 ◽  
Vol 1538 (2-3) ◽  
pp. 329-338 ◽  
Author(s):  
Remko R. Bosch ◽  
Joost G.J. Hoenderop ◽  
Linda van der Heijden ◽  
Jan Joep H.H.M. De Pont ◽  
René J.M. Bindels ◽  
...  
Keyword(s):  
Phospholipase D ◽  
Hormonal Regulation ◽  
Collecting Duct ◽  
Cortical Collecting Duct ◽  
Connecting Tubule

scholarly journals Localization of Inward Rectifier Potassium Channel Kir7.1 in the Basolateral Membrane of Distal Nephron and Collecting Duct

2000 ◽  
Vol 11 (11) ◽  
pp. 1987-1994
Author(s):  
KAYOKO OOKATA ◽  
AKIHIRO TOJO ◽  
YOSHIRO SUZUKI ◽  
NOBUHIRO NAKAMURA ◽  
KENJIRO KIMURA ◽  
...  
Keyword(s):  
Potassium Channel ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Inward Rectifier ◽  
Kidney Cortex ◽  
Thick Ascending Limb ◽  
Cortical Collecting Duct ◽  
Distal Nephron ◽  
Connecting Tubule ◽  
Low K

Abstract. Inward rectifier potassium channels (Kir) play an important role in the K+ secretion from the kidney. Recently, a new subfamily of Kir, Kir7.1, has been cloned and shown to be present in the kidney as well as in the brain, choroid plexus, thyroid, and intestine. Its cellular and subcellular localization was examined along the renal tubule. Western blot from the kidney cortex showed a single band for Kir7.1 at 52 kD, which was also observed in microdissected segments from the thick ascending limb of Henle, distal convoluted tubule (DCT), connecting tubule, and cortical and medullary collecting ducts. Kir7.1 immunoreactivity was detected predominantly in the DCT, connecting tubule, and cortical collecting duct, with lesser expression in the thick ascending limb of Henle and in the medullary collecting duct. Kir7.1 was detected by electron microscopic immunocytochemistry on the basolateral membrane of the DCT and the principal cells of cortical collecting duct, but neither type A nor type B intercalated cells were stained. The message levels and immunoreactivity were decreased under low-K diet and reversed by low-K diet supplemented with 4% KCl. By the double-labeling immunogold method, both Kir7.1 and Na+, K+-ATPase were independently located on the basolateral membrane. In conclusion, the novel Kir7.1 potassium channel is located predominantly in the basolateral membrane of the distal nephron and collecting duct where it could function together with Na+, K+-ATPase and contribute to cell ion homeostasis and tubular K+ secretion.

Cellular origin and hormonal regulation of K+-ATPase activities sensitive to Sch-28080 in rat collecting duct

2000 ◽  
Vol 279 (6) ◽  
pp. F1053-F1059 ◽  
Author(s):  
Nicolas Laroche-Joubert ◽  
Sophie Marsy ◽  
Alain Doucet
Keyword(s):  
Hormonal Regulation ◽  
Collecting Duct ◽  
Type I ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Type Iii ◽  
Principal Cells ◽  
Cellular Origin ◽  
Hormone Effects ◽  
A Cell

Rat collecting ducts exhibit type I or type III K+-ATPase activities when animals are fed a normal (NK) or a K+-depleted diet (LK). This study aimed at determining functionally the cell origin of these two K+-ATPases. For this purpose, we searched for an effect on K+-ATPases of hormones that trigger cAMP production in a cell-specific fashion. The effects of 1-deamino-8-d-arginine vasopressin (dD-AVP), calcitonin, and isoproterenol in principal cells, α-intercalated cells, and β-intercalated cells of cortical collecting duct (CCD), respectively, and of dD-AVP and glucagon in principal and α-intercalated cells of outer medullary collecting duct (OMCD), respectively, were examined. In CCDs, K+-ATPase was stimulated by calcitonin and isoproterenol in NK rats (type I K+-ATPase) and by dD-AVP in LK rats (type III K+-ATPase). In OMCDs, dD-AVP and glucagon stimulated type III but not type I K+-ATPase. These hormone effects were mimicked by the cAMP-permeant analog dibutyryl-cAMP. In conclusion, in NK rats, cAMP stimulates type I K+-ATPase activity in α- and β-intercalated CCD cells, whereas in LK rats it stimulates type III K+-ATPase in principal cells of both CCD and OMCD and in OMCD intercalated cells.

scholarly journals Acute ENaC Stimulation by cAMP in a Kidney Cell Line is Mediated by Exocytic Insertion from a Recycling Channel Pool

2004 ◽  
Vol 125 (1) ◽  
pp. 81-101 ◽  
Author(s):  
Michael B. Butterworth ◽  
Robert S. Edinger ◽  
John P. Johnson ◽  
Raymond A. Frizzell
Keyword(s):  
Hormonal Regulation ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Membrane Capacitance ◽  
Apical Surface ◽  
Cortical Collecting Duct ◽  
Ussing Chambers ◽  
Camp Stimulation

Acute hormonal regulation of the epithelial sodium channel (ENaC) in tight epithelia increases transcellular Na+ transport via trafficking of intracellular channels to the apical surface. The fate of the channels removed from the apical surface following agonist washout is less clear. By repetitively stimulating polarized mouse cortical collecting duct (mCCD, MPKCCD14) epithelia, we evaluated the hypothesis that ENaC recycles through an intracellular pool to be available for reinsertion into the apical membrane. Short circuit current (ISC), membrane capacitance (CT), and conductance (GT) were recorded from mCCD epithelia mounted in modified Ussing chambers. Surface biotinylation of ENaC demonstrated an increase in channel number in the apical membrane following cAMP stimulation. This increase was accompanied by a 83 ± 6% (n = 31) increase in ISC and a 15.3 ± 1.5% (n = 15) increase in CT. Selective membrane permeabilization demonstrated that the CT increase was due to an increase in apical membrane capacitance. ISC and CT declined to basal levels on stimulus washout. Repetitive cAMP stimulation and washout (∼1 h each cycle) resulted in response fatigue; ΔISC decreased ∼10% per stimulation–recovery cycle. When channel production was blocked by cycloheximide, ΔISC decreased ∼15% per stimulation cycle, indicating that newly synthesized ENaC contributed a relatively small fraction of the channels mobilized to the apical membrane. Selective block of surface ENaC by benzamil demonstrated that channels inserted from a subapical pool made up >90% of the stimulated ISC, and that on restimulation a large proportion of channels retrieved from the apical surface were reinserted into the apical membrane. Channel recycling was disrupted by brefeldin A, which inhibited ENaC exocytosis, by chloroquine, which inhibited ENaC endocytosis and recycling, and by latrunculin A, which blocked ENaC exocytosis. A compartment model featuring channel populations in the apical membrane and intracellular recycling pool provided an adequate kinetic description of the ISC responses to repetitive stimulation. The model supports the concept of ENaC recycling in response to repetitive cAMP stimulation.

Similar chloride channels in the connecting tubule and cortical collecting duct of the mouse kidney

2006 ◽  
Vol 290 (6) ◽  
pp. F1421-F1429 ◽  
Author(s):  
Antoine Nissant ◽  
Marc Paulais ◽  
Sahran Lachheb ◽  
Stéphane Lourdel ◽  
Jacques Teulon
Keyword(s):  
Chloride Channels ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Reversal Potential ◽  
Cell Types ◽  
Cortical Collecting Duct ◽  
Patch Clamp Technique ◽  
Connecting Tubule ◽  
Recording Conditions ◽  
Rich Solution

Using the patch-clamp technique, we investigated Cl− channels on the basolateral membrane of the connecting tubule (CNT) and cortical collecting duct (CCD). We found a ∼10-pS channel in CNT cell-attached patches. Substitution of sodium gluconate for NaCl in the pipette shifted the reversal potential by +25 mV, whereas N-methyl-d-gluconate chloride had no effect, indicating anion selectivity. On inside-out patches, we determined a selectivity sequence of Cl− > Br− ∼ NO3− > F−, which is compatible with that of ClC-K2, a Cl− channel in the distal nephron. In addition, the number of open channels ( NPo) measured in cell-attached patches was significantly increased when Ca2+ concentration or pH in the pipette was increased, which is another characteristic of ClC-K. These findings suggest that the basis for this channel is ClC-K2. A similar Cl− channel was found in CCD patches. Because CNT and CCD are heterogeneous tissues, we studied the cellular distribution of the Cl− channel using recording conditions (KCl-rich solution in the pipette) that allowed us to detect simultaneously Cl− channels and inwardly rectifying K+ channels. We detected Cl− channels alone in 45% and 42% and K+ channels alone in 51% and 58% of CNT and CCD patches, respectively. Cl− and K+ channels were recorded simultaneously from two patches (4% of patches) in the CNT and from none of the patches in the CCD. This indicates that Cl− and K+ channels are located in different cell types, which we suggest may be the intercalated cells and principal cells, respectively.

High baseline ROMK activity in mouse late distal convoluted and early connecting tubule (DCT2/CNT) probably contributes to aldosterone-independent K+ secretion

2021 ◽  
Author(s):  
Viatcheslav Nesterov ◽  
Marko Bertog ◽  
Christoph Korbmacher
Keyword(s):  
Single Channel ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Standard Diet ◽  
Cortical Collecting Duct ◽  
Channel Activity ◽  
Connecting Tubule ◽  
Low Potassium ◽  
K Secretion ◽  
Baseline Conditions

The renal outer medullary K+ channel (ROMK) is co-localized with the epithelial Na+ channel (ENaC) in late distal convoluted tubule (DCT2), connecting tubule (CNT) and cortical collecting duct (CCD). ENaC-mediated Na+ absorption generates the electrical driving force for ROMK-mediated tubular K+ secretion which is critically important for maintaining renal K+ homeostasis. ENaC activity is aldosterone-dependent in late CNT and early CCD (CNT/CCD) but aldosterone-independent in DCT2 and early CNT (DCT2/CNT). This suggests that under baseline conditions with low plasma aldosterone ROMK-mediated K+ secretion mainly occurs in DCT2/CNT. Therefore, we hypothesized that baseline ROMK activity is higher in DCT2/CNT than in CNT/CCD. To test this hypothesis, patch-clamp experiments were performed in DCT2/CNT and CNT/CCD microdissected from mice maintained on standard diet. In single-channel recordings from outside-out patches we detected typical ROMK channel activity in both DCT2/CNT and CNT/CCD and confirmed that ROMK is the predominant K+ channel in the apical membrane. Amiloride-sensitive (ΔIami) and tertiapin-sensitive (ΔITPNQ) whole-cell currents were determined to assess ENaC and ROMK activity, respectively. As expected, baseline ΔIami was high in DCT2/CNT (~370 pA) but low in CNT/CCD (~60 pA). Importantly, ΔITPNQ was significantly higher in DCT2/CNT than in CNT/CCD (~810 pA versus ~350 pA). We conclude that high ROMK activity in DCT2/CNT is critical for aldosterone-independent renal K+ secretion under baseline conditions. A low potassium diet significantly reduced ENaC but not ROMK activity in DCT2/CNT. This suggests that modifying ENaC activity in DCT2/CNT plays a key regulatory role in adjusting renal K+ excretion to dietary K+ intake.

scholarly journals Endothelin-1 inhibits sodium reabsorption by ETA and ETB receptors in the mouse cortical collecting duct

2013 ◽  
Vol 305 (4) ◽  
pp. F568-F573 ◽  
Author(s):  
I. Jeanette Lynch ◽  
Amanda K. Welch ◽  
Donald E. Kohan ◽  
Brian D. Cain ◽  
Charles S. Wingo
Keyword(s):  
Hormonal Regulation ◽  
Collecting Duct ◽  
Early Response ◽  
Sodium Reabsorption ◽  
Na Channel ◽  
Cortical Collecting Duct ◽  
Water Excretion ◽  
Endothelin 1 ◽  
Arterial Blood

The collecting duct (CD) is a major renal site for the hormonal regulation of Na homeostasis and is critical for systemic arterial blood pressure control. Our previous studies demonstrated that the endothelin-1 gene (edn1) is an early response gene to the action of aldosterone. Because aldosterone and endothelin-1 (ET-1) have opposing actions on Na reabsorption (JNa) in the kidney, we postulated that stimulation of ET-1 by aldosterone acts as a negative feedback mechanism, acting locally within the CD. Aldosterone is known to increase JNa in the CD, in part, by stimulating the epithelial Na channel (ENaC). In contrast, ET-1 increases Na and water excretion through its binding to receptors in the CD. To date, direct measurement of the quantitative effect of ET-1 on transepithelial JNa in the isolated in vitro microperfused mouse CD has not been determined. We observed that the CD exhibits substantial JNa in male and female mice that is regulated, in part, by a benzamil-sensitive pathway, presumably ENaC. ENaC-mediated JNa is greater in the cortical CD (CCD) than in the outer medullary CD (OMCD); however, benzamil-insensitive JNa is present in the CCD and not in the OMCD. In the presence of ET-1, ENaC-mediated JNa is significantly inhibited. Blockade of either ETA or ETB receptor restored JNa to control rates; however, only ETA receptor blockade restored a benzamil-sensitive component of JNa. We conclude 1) Na reabsorption is mediated by ENaC in the CCD and OMCD and also by an ENaC-independent mechanism in the CCD; and 2) ET-1 inhibits JNa in the CCD through both ETA and ETB receptor-mediated pathways.

Hormonal regulation of inner medullary collecting duct sodium transport

1993 ◽  
Vol 265 (2) ◽  
pp. F159-F173 ◽  
Author(s):  
M. L. Zeidel
Keyword(s):  
Natriuretic Peptide ◽  
Hormonal Regulation ◽  
Collecting Duct ◽  
Interleukin 1 ◽  
Na Channel ◽  
Na Channels ◽  
Cortical Collecting Duct ◽  
Na Transport ◽  
Inner Medullary Collecting Duct ◽  
Medullary Collecting Duct

The inner medullary collecting duct (IMCD) is the final arbiter of renal Na+ excretion, and Na+ transport in this segment is controlled by a wide variety of hormones and renal autacoids. This review examines the mechanisms of IMCD Na+ transport and its regulation using results obtained from micropuncture and microcatheterization studies in the intact animal, as well as data from isolated perfused tubules, freshly prepared cell suspensions, and cultured IMCD cells. Where appropriate, results from closely related tissues such as the cortical collecting duct and model urinary epithelia are examined. Na+ reabsorption in this segment occurs predominantly via apical amiloride-sensitive Na+ channels and basolateral Na(+)-K(+)-adenosinetriphosphatase (Na(+)-K(+)-ATPase). Although there is some evidence for the activities of other transporters such as Na(+)-K(+)-2Cl- and Na-Cl cotransporters and Na+/H+ exchanger, their role in Na+ homeostasis remains undefined. Mineralocorticoids augment the activities of both apical Na+ channels and basolateral Na(+)-K(+)-ATPase by a variety of complex mechanisms. Prostaglandin E2 inhibits Na(+)-K(+)-ATPase and appears to mediate the actions of several peptide hormones, including endothelin, interleukin-1, and atrial natriuretic peptide [ANP-(31-67)]. Several peptides in the ANP family [ANP-(99-126), urodilatin, and brain natriuretic peptide] bind to guanylate cyclase-linked receptors, leading to inhibition of apical Na+ channel function. These mechanisms of regulation of IMCD Na+ transport likely play important roles in total body Na+ balance in health and disease.

scholarly journals Dietary K regulates ROMK channels in connecting tubule and cortical collecting duct of rat kidney

2009 ◽  
Vol 296 (2) ◽  
pp. F347-F354 ◽  
Author(s):  
Gustavo Frindt ◽  
Anish Shah ◽  
Johan Edvinsson ◽  
Lawrence G. Palmer
Keyword(s):  
Collecting Duct ◽  
Rat Kidney ◽  
Outward Current ◽  
Equilibrium Potential ◽  
Cortical Collecting Duct ◽  
Pipette Solution ◽  
Connecting Tubule ◽  
Outward Currents ◽  
High K ◽  
Low K

The activity of ROMK channels in rat kidney tubule cells was assessed as tertiapin-Q (TPNQ)-sensitive current under whole cell clamp conditions. With an external K+ concentration of 5 mM and an internal K+ concentration of 140 mM and the membrane potential clamped to 0 mV, TPNQ blocked outward currents in principal cells of the cortical collecting duct (CCD) outer medullary collecting duct and connecting tubule (CNT). The apparent Ki was 5.0 nM, consistent with its interaction with ROMK. The TPNQ-sensitive current reversed at voltages close to the equilibrium potential for K+. The currents were reduced when the pipette solution contained ATP. In the CCD, the average TPNQ-sensitive outward current ( ISK) was 476 ± 48 pA/cell in control animals on a 1% KCl diet. ISK increased to 1,255 ± 140 pA when animals were maintained on a high-K (10% KCl) diet for 7 days and decreased to 314 ± 46 pA after 7 days on a low-K (0.1% KCl) diet. In the CNT, ISK was 360 ± 30 pA on control, 1,160 ± 110 on high-K, and 166 ± 16 pA on low-K diets. The results indicate that ROMK channel activity is highly regulated by dietary K in both the CCD and the CNT.

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