Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study was undertaken to determine whether the change in cellular Na+ concentration ( [Na+]i) or cellular pH (pHi) is essential for the modulation by Na+/H+ antiporter of the cellular action of arginine vasopressin (AVP) in renal inner medullary collecting duct cells in culture. Extracellular Na+ depletion promptly decreased [Na+]i from 15.8 to 5.4 mM (P less than 0.01), which was closely related to the decrease in pHi (7.19 to 6.97; P less than 0.01). In the presence of 0.5 mM 3-isobutyl-1-methylxanthine, AVP increased cellular cAMP production in a dose-dependent manner. This was significantly blunted in the Na(+)-depleted cells (1 nM AVP; 481.9 vs. 341.0 fmol/micrograms protein; P less than 0.01). When cells were incubated with the Na(+)-depleted medium containing 25 mM NaHCO3, [Na+]i decreased promptly, but the pHi remained unchanged. Under this condition, the AVP-induced increase in cellular cAMP production was not altered (1 nM AVP; 390.9 vs. 334.8 fmol/micrograms protein). Also, after the Na(+)-depleted cells were incubated in 20 mM NH4Cl, which promptly normalized pHi despite the decreased [Na+]i, the response of cAMP production to AVP was restored. Amiloride (1 x 10(-5)-1 x 10(-3) M), which blocks the Na+/H+ exchange, decreased pHi and AVP- and forskolin-induced cAMP production in a dose-dependent manner. These results indicate that the decrease in [Na+]i promptly inhibits AVP-induced cAMP production mediated through the reduction in pHi in renal inner medullary collecting duct cells.
 ...
PMID:pH dependence of inhibition of arginine vasopressin-induced adenosine 3',5'-monophosphate production by cellular sodium depletion in rat renal inner medullary collecting duct cells in culture. 130 26

It has been recently established that adenosine interferes with the ability of arginine vasopressin (AVP) to generate adenosine 3',5'-cyclic monophosphate (cAMP) in inner medullary collecting duct (IMCD) cells in culture. The aim of the current study was to determine whether this interaction of adenosine with AVP is mediated by adenosine from the basolateral (B) and/or the apical (A) surface of the tubule cell. Cells from rat IMCD were grown to confluence in monolayers on porous filters. Adenosine (5 x 10(-8)-10(-4) M) applied to the B or A surface of the cell had no detectable effect on basal cAMP formation. AVP, 10(-9)-10(-6) M, increased cAMP formation from both B and A surfaces of the cell. When AVP was applied to the B surface, 10(-6) M adenosine inhibited AVP-stimulated cAMP formation from the B side only, whereas adenosine at 10(-4) M inhibited cAMP formation from both B and A sides. The inhibitory effect of adenosine was reproduced with N6-cyclohexyladenosine (CHA) from both B and A surfaces. 5'-(N-ethylcarboxamido)adenosine (NECA) and 2',5'-dideoxyadenosine (DDA) inhibited cAMP formation from the B surface only. When AVP was applied to the A surface, the inhibitory effects of adenosine were the same as when AVP was applied to the B surface; CHA, NECA, and DDA inhibited AVP-stimulated cAMP formation from both the B and A surfaces. 1,3-Dipropyl-8-cyclopentylxanthine (DPCPX), an adenosine antagonist with selectivity for the A1 receptor, prevented the inhibitory effects of adenosine, CHA, and NECA on AVP-stimulated cAMP formation.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Differential effect of basolateral and apical adenosine on AVP-stimulated cAMP formation in primary culture of IMCD. 132 8

In cultured cortical collecting duct (CCD) cells, exogenous prostaglandin E2 (PGE2) inhibited arginine vasopressin (AVP)-stimulated adenosine 3',5'-cyclic monophosphate (cAMP) production in a concentration-dependent manner. Although pertussis toxin (PT, 500 ng/ml) alone did not reverse the PGE2-dependent inhibition, PT and staurosporine, a protein kinase C inhibitor, together partially reversed the effect of exogenous PGE2. In contrast, PT completely reversed the inhibition of AVP-dependent cAMP production by sulprostone. These data suggest that exogenous PGE2 can inhibit AVP-stimulated cAMP production and that the inhibitory effects of PGE2 are mediated by staurosporine- and PT-sensitive component(s). Short-term (15-240 min) incubation with phorbol 12-myristate 13-acetate (PMA, 10(-7) M) inhibited PGE2-stimulated cAMP production. Long-term (20 h) incubation with PMA augmented PGE2-stimulated cAMP production. These data provide evidence for the maintenance of a PT-sensitive PGE2-dependent inhibitory pathway of cAMP production in cultured CCD cells. In addition, data are presented that support an inhibitory role for protein kinase C in the effects of PGE2 on the metabolism of cAMP in these cells.
 ...
PMID:PGE2 regulates cAMP production in cultured rabbit CCD cells: evidence for dual inhibitory mechanisms. 133 88

The inner medullary collecting duct (IMCD) of the rat consists of two structurally and functionally distinct segments, i.e., the initial and the terminal IMCD. To identify factors that may regulate the transport function in the IMCD segments, we assessed whether catecholamines, carbachol, prostaglandin E2 (PGE2), bradykinin, glucagon, calcitonin, parathyroid hormone, or epidermal growth factor affects adenosine 3',5'-cyclic monophosphate (cAMP) production in microdissected tubules in the presence and absence of arginine vasopressin (AVP, 0.1 nM). All experiments were performed in the presence of 3-isobutyl-1-methylxanthine, and cAMP was measured by radioimmunoassay. Epinephrine (greater than or equal to 50 nM) and clonidine (greater than or equal to 1 microM) markedly decreased AVP-induced cAMP levels in both IMCD segments. However, phenylephrine did not show an effect. The inhibitory effect of epinephrine was blocked by yohimbine (50 nM) but not by prazosin (50 nM). In isolated perfused terminal IMCDs, epinephrine inhibited AVP-stimulated urea permeability. Isoproterenol (1 microM), in the absence of AVP, caused a significant increase in cAMP level only in the initial IMCD. Propranolol (1 microM) inhibited this isoproterenol effect, but atenolol did not. Dopamine (less than or equal to 1 microM) had no effect on cAMP levels in either IMCD segment. Carbachol, PGE2, and the various peptide hormones had no effect on cAMP levels (+/- AVP) in either IMCD segment. We conclude that an adrenergic beta 2-receptor is present only in the initial IMCD, where its occupation increases cAMP production. We conclude also that an adrenergic alpha 2-receptor is present in both IMCD segments, where its occupation inhibits AVP-induced cAMP production.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Hormone and autacoid regulation of cAMP production in rat IMCD subsegments. 135 41

Platelet-activating factor (PAF) is a vasoactive substance produced in the medulla which may alter Na excretion by the kidney. To examine a possible site and mechanism of action of PAF on the kidney, we evaluated the effects of PAF on transepithelial resistance and intracellular calcium concentration ([Ca2+]i) in cultured rat inner medullary collecting duct cells. Exposure of inner medullary collecting duct (IMCD) cell monolayers to PAF had no significant effect on basal transepithelial resistance. By contrast, incubation of IMCD cells with PAF reversibly blocked the fall in transepithelial resistance induced by arginine vasopressin (AVP): -11.1 +/- 1.4 omega.cm2 with AVP versus -0.02 +/- 1.6 omega.cm2 with PAF and AVP. Exposure of IMCD cells to PAF in Ca-replete medium caused a rise in intracellular calcium from 155 +/- 25 to 491 +/- 68 nM. By contrast, exposure of IMCD cells to PAF in Ca-free medium produced no change in [Ca2+]i. Because the rise in [Ca2+]i induced by PAF was absent in Ca-free medium, transepithelial resistance across IMCD monolayers was examined in calcium-free medium. The effect of PAF to block the fall in transepithelial resistance induced by AVP was maintained in Ca-free medium. These data suggest that PAF modulates the effect of AVP on conductive channels by a mechanism distinct from changes in intracellular calcium.
 ...
PMID:Platelet-activating factor attenuates the arginine vasopressin-induced fall of transepithelial resistance across inner medullary collecting duct monolayers. 140 7

Immunodissected rabbit cortical collecting duct (CCD) cells were grown in primary culture on permeable membrane supports. Transepithelial voltage, Na+, K+, and H+ gradients developed as expected for a mixed population of principal and intercalated cells. The amiloride-sensitive short-circuit current (Isc) was measured in Ussing chambers as an index of Na+ transport via apical membrane Na+ channels. Treatment of the cells in culture with 10 nM aldosterone for 48 h increased Isc from 7.4 +/- 1.4 to 19.3 +/- 3.2 microA/cm2. In contrast to the native rabbit CCD, 220 pM arginine vasopressin (AVP) produced a rapid and stable (greater than 60 min) increase in Isc to 15.8 +/- 2.0 and 29.0 +/- 3.8 microA/cm2 in untreated and aldosterone-treated cultures, respectively. Although prostaglandin E2 (PGE2) inhibits Na+ transport in the native rabbit CCD, it did not in the cultured cells, and it has previously been shown that PGE2 inhibition of AVP-dependent adenosine 3',5'-cyclic monophosphate production is lost in culture (W. K. Sonnenburg and W. L. Smith, J. Biol. Chem. 263: 6155-6160, 1988). We conclude that the development of a stable stimulation of Na+ transport by AVP is linked to the loss of the inhibitory effects of PGE2.
 ...
PMID:AVP stimulates Na+ transport in primary cultures of rabbit cortical collecting duct cells. 155 62

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)
 ...
PMID:Muscarinic receptor activation inhibits AVP-induced water flow in rabbit cortical collecting ducts. 164 93

A cortical collecting duct (CCD) cell line has been developed from a mouse transgenic for the early region of simian virus 40, Tg(SV40E)Bri/7. CCDs were microdissected and placed on collagen gels. Monolayers were subsequently subcultured onto permeable collagen membranes and maintained in serum-supplemented medium. One line, designated M-1, retained many characteristics of the CCD, including a typical epithelial appearance and CCD-specific antigens. M-1 cells, when grown in monolayers on permeable supports, exhibited a high transepithelial resistance (885.7 +/- 109.6 ohms/cm2) and developed a lumen negative transepithelial potential difference (PD) of -45.7 +/- 3.5 mV. The associated short-circuit current (SCC) averaged 71.8 +/- 10.3 microA/cm2, and was reduced by 95% by luminal application of amiloride. The cultured cells responded to arginine vasopressin (AVP) with a significant increase in SCC. M-1 cells generated significant transepithelial solute gradients. After 24 hours incubation, the composition of the luminal (L) and basolateral (B) media (in mM) was: [Na+], L = 106.7 +/- 0.9 and B = 127.4 +/- 0.4; [K+], L = 8.6 +/- 0.6 and B = 2.1 +/- 0.3; [Cl], L = 68.6 +/- 5.8 and B = 101.8 +/- 6.6; [HCO3], L = 15.5 +/- 1.5 and B = 8.6 +/- 1.2; while pH was 7.16 +/- 0.03 at the luminal and 6.94 +/- 0.03 at the basolateral side. The formation of these concentration gradients indicates that the CCD cultures absorb Na+ and Cl- and secrete K+.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Characterization of a mouse cortical collecting duct cell line. 165 78

We investigated the tubular action of endothelin in rat nephron segments. The effects of endothelin on arginine vasopressin (AVP)-, parathyroid hormone-, glucagon-, calcitonin-, and isoproterenol-dependent cAMP accumulation were studied. The following nephron segments were microdissected: glomerulus (Gl), proximal convoluted tubule (PCT), cortical and medullary thick ascending limbs of Henle's loop (cTAL and mTAL, respectively), cortical collecting duct (CCD), outer medullary collecting duct (OMCD), and inner medullary collecting duct (IMCD). Endothelin dose dependently (10(-8)-10(-10)M) inhibited AVP-dependent cAMP accumulation in CCD, OMCD, and IMCD. This effect was independent of the presence or absence of phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine, Ca channel blocker nicardipine, or indomethacin, but was abolished in the presence of protein kinase C inhibitor H-7. Protein kinase C stimulator dioctanoyl glycerol mimicked the effect of endothelin. On the other hand, endothelin had no inhibitory effect on AVP-dependent cAMP accumulation in cTAL or mTAL, parathyroid hormone-dependent cAMP accumulation in Gl and PCT, or glucagon-, calcitonin-, and isoprotereol-dependent cAMP accumulation in OMCD. We conclude that endothelin specifically inhibits AVP-dependent cAMP accumulation in CCD, OMCD, and IMCD through activating protein kinase C. This effect possibly has a role in maintaining urine volume to counteract the decrease in GFR caused by endothelin itself.
 ...
PMID:Effects of endothelin on peptide-dependent cyclic adenosine monophosphate accumulation along the nephron segments of the rat. 169 79

The inner medullary collecting duct (IMCD) is an important site of action for arginine vasopressin (AVP). To examine the mode of action of AVP in this segment, we measured the change in transepithelial resistance of cultured rat IMCD cells grown to confluence on collagen-coated Millicell culture plate inserts in response to AVP. Resistance was measured by use of an EVOM voltage-ohm meter. AVP at 10(-11)-10(-8) M caused a fall in resistance of 6.9 +/- 1.3 to 14.0 +/- 1.4 omega.cm2 (P less than 0.05 to less than 0.01 vs. no AVP), which was reversed by removal of AVP or addition of 10(-6) M amiloride. Pretreating the apical surface of IMCD cells with trypsin had no effect on resistance but totally prevented the antidiuretic hormone-induced fall in resistance. Pretreating the apical surface with trypsin and amiloride did not prevent the fall in resistance to AVP. Addition of 10(-9) M AVP or 10(-6) M forskolin increased 2-min adenosine 3',5'-cyclic monophosphate (cAMP) accumulation by 55 or 96%, respectively. Stimulation of endogenous cAMP accumulation by forskolin or the addition of exogenous 8-bromo-cAMP caused no change in resistance. To examine the relationship between intracellular calcium [( Ca2+]i) and AVP action, the response of [Ca2+]i to AVP was measured by use of fura-2. AVP induced no change in [Ca2+]i in IMCD cells in suspension, on glass cover slips, or on permeable supports. Ionomycin (25 nM) increased [Ca2+]i in IMCD cells and lowered resistance across monolayers, but the fall in resistance was not blocked by amiloride.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:AVP reduces transepithelial resistance across IMCD cell monolayers. 169 8


1 2 3 4 5 6 7 8 9 10 Next >>