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)

In amphibian bladder, arginine vasopressin (AVP) depolymerizes F-actin in the apical region of the granular cell, promoting fusion of water channel-carrying vesicles with the apical membrane. We now report the effect of AVP on F-actin in the mid- and terminal segments of rat inner medullary collecting duct (IMCD2 and IMCD3). In IMCD3, 5 min of stimulation by 2.5-250 nM AVP significantly depolymerized F-actin by 13-24% in whole cell assays employing the rhodamine-phalloidin binding technique. The IMCD2 was more sensitive, responding to subnanomolar (0.25 nM) AVP with 6 +/- 2% depolymerization. Depolymerization occurred as early as 2 min after 2.5 and 25 nM but not 250 nM AVP. 8-Bromoadenosine 3',5'-cyclic monophosphate depolymerized F-actin in IMCD3 at both 2 and 5 min. Immunogold labeling of the apical actin pool in IMCD3 principal cells was reduced by 26 +/- 5% (P < 0.05) by 2.5 nM AVP; the lateral and basal pools showed no significant changes. Capillary endothelial, thin limb of Henle, and intercalated cells showed no changes in immunogold labeling after AVP. Thus reorganization of the apical actin network by AVP is a consistent finding in both mammalian and amphibian target cells.
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PMID:Vasopressin depolymerizes apical F-actin in rat inner medullary collecting duct. 821 31

Peritubular arginine vasopressin (AVP) regulates bicarbonate reabsorption in the cortical distal tubule via V(1) and V(2) receptors. The dose-dependent effects of peritubular AVP on net bicarbonate reabsorption (J(HCO)) were evaluated by stationary microperfusion of in vivo early (ED; distal convoluted tubule) and late distal (LD; connecting tubule and initial collecting duct) segments of rat kidney, using double-barreled H(+)-sensitive, ion-exchange resin/reference (1 M KCl) microelectrodes. AVP (10(-11) M) perfused into peritubular capillaries increased J(HCO), compared with basal levels during intact capillary perfusion with blood, in ED and LD segments. AVP (10(-9) M) also increased J(HCO) in both segments, but the effect of AVP (10(-11) M) was significantly higher. A specificV(1)-receptor antagonist alone or with AVP (10(-11) or 10(-9) M) reduced J(HCO) below basal levels. A specific V(2)-receptor antagonist alone or plus AVP (10(-11) M) did not affect J(HCO) but increased AVP (10(-9) M)-mediated stimulation. 8-Bromoadenosine 3',5'-cyclic monophosphate alone reduced J(HCO) below basal levels and also reduced AVP (10(-11) M)-mediated stimulation. (Deamino-Cys(1), D-Arg(8)) vasopressin (a V(2)-selective agonist) also reduced J(HCO) below basal levels. These results show that peritubular AVP stimulates J(HCO) in ED and LD segments via basolateral V(1) receptors and that basolateral V(2) receptors have a dose-dependent inhibitory effect mediated by cAMP. The data also indicate that endogenous AVP stimulates distal J(HCO) via basolateral V(1) receptors.
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PMID:Peritubular AVP regulates bicarbonate reabsorption in cortical distal tubule via V(1) and V(2) receptors. 1178 39

Alkalosis impairs the natriuretic response to diuretics, but the underlying mechanisms are unclear. The soluble adenylyl cyclase (sAC) is a chemosensor that mediates bicarbonate-dependent elevation of cAMP in intracellular microdomains. We hypothesized that sAC may be an important regulator of Na(+) transport in the kidney. Confocal images of rat kidney revealed specific immunolocalization of sAC in collecting duct cells, and immunoblots confirmed sAC expression in mouse cortical collecting duct (mpkCCD(c14)) cells. These cells exhibit aldosterone-stimulated transepithelial Na(+) currents that depend on both the apical epithelial Na(+) channel (ENaC) and basolateral Na(+),K(+)-ATPase. RNA interference-mediated 60-70% knockdown of sAC expression comparably inhibited basal transepithelial short circuit currents (I(sc)) in mpkCCD(c14) cells. Moreover, the sAC inhibitors KH7 and 2-hydroxyestradiol reduced I(sc) in these cells by 50-60% within 30 min. 8-Bromoadenosine-3',5'-cyclic-monophosphate substantially rescued the KH7 inhibition of transepithelial Na(+) current. Aldosterone doubled ENaC-dependent I(sc) over 4 h, an effect that was abolished in the presence of KH7. The sAC contribution to I(sc) was unaffected with apical membrane nystatin-mediated permeabilization, whereas the sAC-dependent Na(+) current was fully inhibited by basolateral ouabain treatment, suggesting that the Na(+),K(+)-ATPase, rather than ENaC, is the relevant transporter target of sAC. Indeed, neither overexpression of sAC nor treatment with KH7 modulated ENaC currents in Xenopus oocytes. ATPase and biotinylation assays in mpkCCD(c14) cells demonstrated that sAC inhibition decreases catalytic activity rather than surface expression of the Na(+),K(+)-ATPase. In summary, these results suggest that sAC regulates both basal and agonist-stimulated Na(+) reabsorption in the kidney collecting duct, acting to enhance Na(+),K(+)-ATPase activity.
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PMID:Regulation of epithelial Na+ transport by soluble adenylyl cyclase in kidney collecting duct cells. 1912 49