Intracellular Ca2+ and PKC activation do not inhibit Na+ and water transport in rat CCD

1993 ◽  
Vol 265 (4) ◽  
pp. F569-F577 ◽  
Author(s):  
A. J. Rouch ◽  
L. Chen ◽  
L. H. Kudo ◽  
P. D. Bell ◽  
B. C. Fowler ◽  
...  
Keyword(s):  
Water Transport ◽  
Calcium Concentration ◽  
Morphological Changes ◽  
Collecting Duct ◽  
Bathing Solution ◽  
Cortical Collecting Duct ◽  
Kinase C ◽  
Transepithelial Voltage ◽  
Pkc Activation ◽  
Sustained Increase

Experiments examined the effects of elevation of intracellular calcium concentration ([Ca2+]i) or activation of protein kinase C (PKC) on Na+ and water transport in the rat cortical collecting duct (CCD). We measured the lumen-to-bath 22Na+ flux (J1-->b), transepithelial voltage (VT), and water permeability (Pf) in CCD from deoxycorticosterone (DOC)-treated rats. Ionomycin (0.5 and 1 microM) and thapsigargin (1 and 2 microM) were used to increase [Ca2+]i. Phorbol 12-myristate 13-acetate (PMA; 0.3 and 1 microM) and oleoyl-acetyl-glycerol (OAG; 100 microM) were used as activators of PKC. [Ca2+]i was measured in isolated perfused tubules using the fluorescent dye fura 2. When added to the bathing solution, 220 pM arginine vasopressin (AVP) failed to affect [Ca2+]i, whereas 1 microM ionomycin increased [Ca2+]i by 103 +/- 15% and 2 microM thapsigargin increased [Ca2+]i by 24 +/- 4%. In flux studies, neither ionomycin nor thapsigargin affected J1-->b or Pf, although ionomycin caused marked morphological changes. Ionomycin also failed to alter either parameter in tubules from non-DOC-treated rats. Neither 100 microM OAG nor 1 microM PMA affected J1-->b or Pf. OAG at 50 microM had no effect on VT or transepithelial resistance, indicating no inhibition of conductive Na+ transport. We conclude that increased [Ca2+]i and PKC activation do not affect J1--b or Pf in the rat CCD. These findings may account for the sustained increase in J1--b produced in the rat CCD by AVP.

Adenosine-stimulated Ca2+reabsorption is mediated by apical A1 receptors in rabbit cortical collecting system

1998 ◽  
Vol 274 (4) ◽  
pp. F736-F743 ◽  
Author(s):  
Joost G. J. Hoenderop ◽  
Anita Hartog ◽  
Peter H. G. M. Willems ◽  
René J. M. Bindels
Keyword(s):  
Collecting Duct ◽  
Cortical Collecting Duct ◽  
Concomitant Increase ◽  
Cgs 21680 ◽  
Kinase C ◽  
Intracellular Ca ◽  
Collecting Duct Cells ◽  
Camp Formation ◽  
Pkc Activation ◽  
Permeable Supports

Confluent monolayers of immunodissected rabbit connecting tubule and cortical collecting duct cells, cultured on permeable supports, were used to study the effect of adenosine on net apical-to-basolateral Ca2+ transport. Apical, but not basolateral, adenosine increased this transport dose dependently from 48 ± 3 to 110 ± 4 nmol ⋅ h−1 ⋅ cm−2. Although a concomitant increase in cAMP formation suggested the involvement of an A2 receptor, the A2 agonist CGS-21680 did not stimulate Ca2+ transport, while readily increasing cAMP. By contrast, the A1 agonist N 6-cyclopentyladenosine (CPA) maximally stimulated Ca2+transport without significantly affecting cAMP. Adenosine-stimulated transport was effectively inhibited by the A1 antagonist 1,3-dipropyl-8-cyclopenthylxanthine but not the A2 antagonist 3,7-dimethyl-1-propargylxanthine, providing additional evidence for the involvement of an A1 receptor. Both abolishment of the adenosine-induced transient increase in intracellular Ca2+ concentration by 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid and downregulation of protein kinase C (PKC) by prolonged phorbol ester treatment were without effect on adenosine-stimulated Ca2+ transport. The data presented suggest that adenosine interacts with an apical A1 receptor to stimulate Ca2+ transport via a hitherto unknown pathway that does not involve cAMP formation, PKC activation, and/or Ca2+ mobilization.

Evidence that separate PGE2 receptors modulate water and sodium transport in rabbit cortical collecting duct

1993 ◽  
Vol 265 (5) ◽  
pp. F643-F650 ◽  
Author(s):  
R. L. Hebert ◽  
H. R. Jacobson ◽  
D. Fredin ◽  
M. D. Breyer
Keyword(s):  
Pertussis Toxin ◽  
Water Permeability ◽  
Sodium Transport ◽  
Collecting Duct ◽  
Inhibitory Effect ◽  
Cortical Collecting Duct ◽  
Pkc Inhibitor ◽  
Kinase C ◽  
Pge2 Receptor ◽  
Pkc Activation

Prostaglandin E2 (PGE2) modulates both water and sodium transport in the rabbit cortical collecting duct (CCD). To determine whether these effects are mediated by separate PGE2 receptors, we compared the effects of PGE2 and its analogue sulprostone in the isolated perfused rabbit CCD. PGE2 increased basal water permeability (hydraulic conductivity), whereas sulprostone did not. PGE2 and sulprostone were equipotent inhibitors of water absorption when it was prestimulated by vasopressin. Pertussis toxin completely reversed the inhibitory effect of sulprostone but only partially reversed the inhibitory effect of PGE2. In contrast, a protein kinase C (PKC) inhibitor, staurosporine, partially reversed the inhibitory effect of PGE2 but had no effect on sulprostone. PGE2 also raised intracellular calcium ([Ca2+]i). This effect is coupled to its capacity to inhibit Na+ absorption. Sulprostone was 10-fold less potent than PGE2 both in raising [Ca2+]i or inhibiting sodium transport. The results suggest sulprostone selectively interacts with a PGE2 receptor coupled to pertussis toxin-sensitive inhibition of water permeability. Sulprostone less potently activates a PGE2 receptor coupled to [Ca2+]i, PKC activation, and sodium transport and completely fails to interact with the PGE2 receptor that stimulates water permeability in the collecting duct. These results suggest distinct PGE2 receptors modulate sodium and water transport in the CCD.

Interleukin-1 inhibits sodium and water transport in rabbit cortical collecting duct

1994 ◽  
Vol 266 (4) ◽  
pp. F674-F680 ◽  
Author(s):  
Y. Sakairi ◽  
Y. Ando ◽  
K. Tabei ◽  
E. Kusano ◽  
Y. Asano
Keyword(s):  
Water Transport ◽  
Collecting Duct ◽  
Interleukin 1 ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Cortical Collecting Duct ◽  
Direct Inhibitory Effect ◽  
Transepithelial Voltage ◽  
Dose Dependent

Interleukin-1 (IL-1) induces natriuresis and diuresis. In the present study, the effect of basolateral IL-1 on sodium and water transport was examined in the cortical collecting duct (CCD) perfused in vitro. IL-1, 10 pg/ml and 10 ng/ml, inhibited lumen-to-bath sodium flux (JNa, peq.min-1.mm tubule-1), depolarizing transepithelial voltage (Vt) in a time- and dose-dependent manner. The inhibitory effect of 10 ng/ml but not 10 pg/ml IL-1 on Vt and JNa was mitigated by 5 microM indomethacin (IND) in bath. Also, 10 ng/ml IL-1, which did not affect the basal hydraulic conductivity (Lp, x10(-7) cm.atm-1.s-1) by itself, inhibited the hydrosmotic effect of 20 pM basolateral arginine vasopressin, and 5 microM IND abolished this inhibitory effect of 10 ng/ml IL-1. The present study demonstrated direct inhibitory effect of basolateral IL-1 on sodium and water reabsorption in the rabbit CCD. The effect of IL-1 is suggested to be mediated, in part, by a cyclooxygenase metabolite(s).

Muscarinic receptor activation inhibits AVP-induced water flow in rabbit cortical collecting ducts

1991 ◽  
Vol 260 (6) ◽  
pp. F929-F936 ◽  
Author(s):  
H. M. Snyder ◽  
D. M. Fredin ◽  
M. D. Breyer
Keyword(s):  
Muscarinic Receptor ◽  
Water Flow ◽  
Calcium Concentration ◽  
Collecting Duct ◽  
Receptor Activation ◽  
Inhibitory Effect ◽  
Cortical Collecting Duct ◽  
Kinase C ◽  
Collecting Ducts ◽  
Subsequent Addition

We examined the effect of carbachol, an acetylcholine analogue, on hydraulic conductivity (Lp) response to 10 microU/ml arginine vasopressin (AVP) in rabbit cortical collecting duct (CCD). In CCDs in which water flow had been established with AVP, subsequent addition of carbachol caused Lp (X10(-7) cm.atm-1.s-1) to fall from 251 +/- 32 to 146 +/- 19. Carbachol washout resulted in recovery of Lp to 217 +/- 38. In CCDs in which water flow had been established using 10(-4) M 8-chlorophenylthioadenosine 3',5'-cyclic monophosphate (8-CPT-cAMP), addition of carbachol had no effect. These posttreatment studies suggest that carbachol's effects on modulating established water flow occur at a "pre-cAMP" step. With carbachol added first, AVP-induced Lp was reduced from 233 +/- 24 (controls) to 105 +/- 19 (carbachol-pretreated). Pretreatment with 10(-6) M atropine, a muscarinic receptor antagonist, totally reversed the inhibitory effect of carbachol, consistent with a receptor-mediated effect of carbachol. Carbachol pretreatment also inhibited 8-CPT-cAMP-induced Lp, indicating that carbachol's effects also occur at a "post-cAMP" step. Pretreatment with 10(-7) M staurosporine, a protein kinase C (PKC) inhibitor, reversed inhibitory effect of carbachol on AVP-induced Lp (193 +/- 26), suggesting that carbachol's effects are mediated by PKC. Intracellular calcium concentration [( Ca2+]i) was measured in fura-2-loaded CCDs. Carbachol also increased [Ca2+]i from 229 +/- 120 to 389 +/- 160 nM.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanism of bradykinin, ADH, and cAMP interaction in rabbit cortical collecting duct

1985 ◽  
Vol 249 (5) ◽  
pp. F645-F653 ◽  
Author(s):  
V. L. Schuster
Keyword(s):  
Collecting Duct ◽  
Prostaglandin Synthesis ◽  
Regulatory Subunit ◽  
Cortical Collecting Duct ◽  
Camp Generation ◽  
Osmotic Water ◽  
Transepithelial Voltage ◽  
Collecting Tubules ◽  
Prostaglandin Synthesis Inhibitors ◽  
Osmotic Water Flow

Vasopressin (ADH) and bradykinin (BK) have been shown to stimulate prostaglandin synthesis in rabbit cortical collecting tubules. We studied ADH and BK effects on osmotic water flow (Lp), Na transport (JNa), and transepithelial voltage (VT). Bath BK but not lumen BK blunted subsequent ADH hydroosmotic responses. This BK effect was prevented by ibuprofen or pertussigen pretreatment and was overcome with exogenous cAMP, suggesting that BK, via prostaglandins, interferes with ADH action on Lp at the cAMP generation step. In contrast, bath BK had no effect on bath-to-lumen (Jb-1Na) or lumen-to-bath (Jl-bNa) Na flux or on VT. As reported by others, ADH lowered Jl-bNa and depolarized VT; however, prostaglandin synthesis inhibitors neither prevented nor reversed these ADH effects. Together, these BK and ADH data do not support regulation of JNa by peptide-stimulated prostaglandins. Moreover, cAMP alone depolarized VT but had no effect on Jl-bNa. Therefore, ADH-induced depolarization of VT may at least partly owe to cAMP effects on VT independent of accompanying changes in JNa. As with Lp, bath BK blunted subsequent ADH effects on VT and, to a lesser extent, Jl-bNa; these BK effects on ADH action were also prevented by ibuprofen or pertussigen pretreatment. The data are consistent with the following model: 1) ADH depolarizes VT and increases Lp via cAMP; 2) ADH decreases JNa via neither cAMP nor prostaglandins; and 3) BK, via prostaglandins, inhibits the actions of ADH on Lp and VT at the inhibitory guanyl-nucleotide regulatory subunit of adenylate cyclase.

Effect of insulin on potassium secretion in rabbit cortical collecting ducts

1992 ◽  
Vol 262 (1) ◽  
pp. F30-F35 ◽  
Author(s):  
H. Furuya ◽  
K. Tabei ◽  
S. Muto ◽  
Y. Asano
Keyword(s):  
Collecting Duct ◽  
Dependent Manner ◽  
Cortical Collecting Duct ◽  
Plasma Insulin Concentration ◽  
Concentration Dependent Manner ◽  
K Secretion ◽  
Potassium Secretion ◽  
Transepithelial Voltage ◽  
K Transport

Insulin is known to play an important role in the regulation of extrarenal K homeostasis. Previous clearance studies have shown that insulin decreases urinary K excretion, but the responsible nephron segments have not been identified. In this microperfusion study, in vitro, the effect of insulin on K transport in the cortical collecting duct (CCD), which is thought to be an important segment for regulation of the final urinary K excretion, was investigated. Basolateral insulin (10(-6) M) significantly inhibited net K secretion by 20% (mean JK = -26.2 +/- 4.2 peq.mm-1.min-1 for controls compared with -21.1 +/- 3.4 with insulin, P less than 0.001) and depolarized the transepithelial voltage (VT, from -14.6 +/- 3.5 to -10.8 +/- 3.5 mV, P less than 0.005), recovery did not occur over 60 min. Insulin (10(-11)-10(-5) M) depressed K secretion and depolarized the VT in a concentration-dependent manner. The half-maximal concentration was 5 x 10(-10) M, which is within the physiological range of plasma insulin concentration. In tubules of deoxycorticosterone acetate-treated rabbits, insulin also produced a significant fall in K secretion (from -43.4 +/- 7.5 to -36.1 +/- 5.7 peq.mm-1.min-1, P less than 0.05). Although luminal Ba (2 mM) decreased K secretion (from -14.4 +/- 2.9 to -7.0 +/- 1.7 peq.mm-1.min-1), basolateral insulin (10(-6) M) inhibited K secretion further (to -4.7 +/- 1.3 peq.mm-1.min-1, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Functional characterization of basolateral and luminal dopamine receptors in rabbit CCD

2001 ◽  
Vol 281 (1) ◽  
pp. F114-F122 ◽  
Author(s):  
Osamu Saito ◽  
Yasuhiro Ando ◽  
Eiji Kusano ◽  
Yasushi Asano
Keyword(s):  
Receptor Agonist ◽  
Collecting Duct ◽  
Functional Characterization ◽  
Receptor Subtypes ◽  
Cortical Collecting Duct ◽  
Basolateral Side ◽  
Skf 81297 ◽  
Transepithelial Voltage ◽  
Specific Antagonist

Previous studies reported the existence of both D1- and D2-like receptors in the cortical collecting duct (CCD). However, especially with regard to natriuresis, it remains controversial. In the present study, rabbit CCD was perfused to characterize the receptor subtypes responsible for the tubular actions. Basolateral dopamine (DA) induced a dose-dependent depolarization of transepithelial voltage. Basolateral domperidone, a D2-like receptor antagonist, abolished depolarization, whereas SKF-81297, a D1-like receptor agonist, showed no significant change. In addition, bromocriptine, a D2-like receptor agonist, also caused depolarization, whereas SKF-81297, a D1-like receptor agonist, did not depolarize significantly. Moreover, RBI-257, a D4-specific antagonist, reversed the basolateral DA-induced depolarization. In contrast to the basolateral side, luminal DA caused depolarization via a D1-like receptor; however the change was less than that for basolateral DA. For further evaluation, 22Na+ flux ( J Na) was measured to confirm the effect of DA on Na+ transport. Basolateral DA also caused a suppression of J Na, and this reaction was abolished by domperidone. These results suggested that the basolateral D2-like receptor is mainly responsible for the natriuretic action of DA in rabbit CCD.

scholarly journals ENaC inhibition stimulates HCl secretion in the mouse cortical collecting duct. I. Stilbene-sensitive Cl− secretion

2015 ◽  
Vol 309 (3) ◽  
pp. F251-F258 ◽  
Author(s):  
Masayoshi Nanami ◽  
Yoskaly Lazo-Fernandez ◽  
Vladimir Pech ◽  
Jill W. Verlander ◽  
Diana Agazatian ◽  
...  
Keyword(s):  
Channel Blocker ◽  
Single Channel ◽  
Collecting Duct ◽  
Cortical Collecting Duct ◽  
Collecting Ducts ◽  
Hcl Secretion ◽  
Transepithelial Voltage ◽  
Apical Membranes ◽  
Rats And Mice

Inhibition of the epithelial Na+ channel (ENaC) reduces Cl− absorption in cortical collecting ducts (CCDs) from aldosterone-treated rats and mice. Since ENaC does not transport Cl−, the purpose of the present study was to explore how ENaC modulates Cl− absorption in mouse CCDs perfused in vitro. Therefore, we measured transepithelial Cl− flux and transepithelial voltage in CCDs perfused in vitro taken from mice that consumed a NaCl-replete diet alone or the diet with aldosterone administered by minipump. We observed that application of an ENaC inhibitor [benzamil (3 μM)] to the luminal fluid unmasks conductive Cl− secretion. During ENaC blockade, this Cl− secretion fell with the application of a nonselective Cl− channel blocker [DIDS (100 μM)] to the perfusate. While single channel recordings of intercalated cell apical membranes in split-open CCDs demonstrated a Cl− channel with properties that resemble the ClC family of Cl− channels, ClC-5 is not the primary pathway for benzamil-sensitive Cl− flux. In conclusion, first, in CCDs from aldosterone-treated mice, most Cl− absorption is benzamil sensitive, and, second, benzamil application stimulates stilbene-sensitive conductive Cl− secretion, which occurs through a ClC-5-independent pathway.

Inhibition of Na+ and Ca2+ reabsorption by P2u purinoceptors requires PKC but not Ca2+ signaling

1996 ◽  
Vol 270 (1) ◽  
pp. F53-F60 ◽  
Author(s):  
H. P. Koster ◽  
A. Hartog ◽  
C. H. van Os ◽  
R. J. Bindels
Keyword(s):  
Inhibitory Concentration ◽  
Purinergic Receptor ◽  
Rank Order ◽  
Collecting Duct ◽  
Cortical Collecting Duct ◽  
Inhibitory Effects ◽  
Maximal Inhibition ◽  
Kinase C ◽  
Collecting Duct Cells ◽  
Dose Dependent

Rabbit connecting tubule and cortical collecting duct cells were isolated by immunodissection and cultured to confluence on permeable filters and on glass coverslips. Extracellular ATP dose-dependently reduced transcellular Na+ and Ca2+ transport (half-maximal inhibitory concentration, IC50, of 0.5 +/- 0.2 and 3.2 +/- 0.5 microM), with a maximal inhibition of 57 +/- 5 and 43 +/- 4%, respectively. Purinergic receptor agonists inhibited transport with the following rank order of potency: UTP = ATP > ADP; this suggests involvement of P2u purinoceptors. ATP also caused a dose-dependent (50% effective dose, EC50, of 1.5 +/- 0.2 microM) transient increase in intracellular Ca2+ concentration ([Ca2+]i), which decreased to a sustained elevated level. In the absence of extracellular Ca2+, a similar Ca2+ transient occurred, but the sustained response was abolished. Preloading the cells with the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) completely prevented the ATP-induced Ca2+ transients, but not the ATP-induced inhibition of Na+ and Ca2+ absorption. Activation of protein kinase C (PKC) by the cell-permeable diacylglycerol analogue, 1,2-dioctanoyl-en-glycerol, mimicked ATP-induced inhibition of Na+ and Ca2+ absorption. The inhibitory effects of ATP were no longer observed after culturing cells in the presence of phorbol ester (12-O-tetradecanoylphorbol-13-acetate) for 5 days, which resulted in downregulation of cellular PKC activity.

scholarly journals Interleukin-6 stimulates epithelial sodium channels in mouse cortical collecting duct cells

2010 ◽  
Vol 299 (2) ◽  
pp. R590-R595 ◽  
Author(s):  
Ke Li ◽  
Dehuang Guo ◽  
Haidong Zhu ◽  
Kathleen S. Hering-Smith ◽  
L. Lee Hamm ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Sodium Current ◽  
Collecting Duct ◽  
Sodium Reabsorption ◽  
Cortical Collecting Duct ◽  
Epithelial Sodium Channels ◽  
Duct Cells ◽  
Transepithelial Voltage ◽  
Collecting Duct Cells ◽  
Pressure Natriuresis

The aim of this study is to elucidate the effects of interleukin-6 (IL-6) on the expression and activity of the epithelial sodium channel (ENaC), which is one of the key mechanisms underlying tubular sodium reabsorption. M-1 cortical collecting duct cells were treated with IL-6 (100 ng/ml) for 12 h. Real-time polymerase chain reaction and immunoblotting were employed to examine the mRNA and protein abundance. Transepithelial voltage ( Vte) and resistance ( Rte) were measured with an ohm/voltmeter (EVOM, WPI). The equivalent current was calculated as the ratio of Vte to Rte. Treatment with IL-6 ( n = 5) increased the mRNA abundance of α-ENaC by 11 ± 7% ( P = not significant), β-ENaC by 78 ± 14% ( P = 0.01), γ-ENaC by 185 ± 38% ( P = 0.02), and prostasin by 29 ± 5% ( P = 0.01), all normalized by β-actin. Treatment with IL-6 increased the protein expression of α-ENaC by 19 ± 3% ( P = 0.001), β-ENaC by 89 ± 21% ( P = 0.01), γ-ENaC by 36 ± 12% ( P = 0.02), and prostasin by 33 ± 6% ( P = 0.02). The amiloride-sensitive sodium current increased by 37 ± 5%, from 6.0 ± 0.4 to 8.2 ± 0.3 μA/cm2 ( P < 0.01), in the cells treated with IL-6 compared with controls ( P = 0.01). Aprotinin (28 μg/ml), a prostasin inhibitor, reduced the amiloride-sensitive sodium current by 61 ± 5%, from 6.1 ± 0.3 to 3.7 ± 0.2 μA/cm2 ( P = 0.01). The magnitude of the IL-6-induced amiloride-sensitive sodium current in the presence of aprotinin dropped by 57 ± 2%, from 8.6 ± 0.2 to 4.9 ± 0.2 μA/cm2 ( P < 0.01). This study has identified a novel function of IL-6, namely, IL-6 may activate ENaC. Therefore, renal inflammation mediated by IL-6 likely contributes to impaired pressure natriuresis.

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