External Ni2+ and ENaC in A6 cells: Na+ current stimulation by competition at a binding site for amiloride and Na+

DC FieldValueLanguage
dc.contributor.authorCucu, D
dc.contributor.authorSimaels, J
dc.contributor.authorVan Driessche, W
dc.contributor.authorZeiske, W
dc.date.accessioned2021-12-23T16:09:12Z-
dc.date.available2021-12-23T16:09:12Z-
dc.date.issued2003
dc.identifier.issn00222631
dc.identifier.urihttps://osnascholar.ub.uni-osnabrueck.de/handle/unios/8667-
dc.description.abstractIn cultured A6 monolayers from distal Xenopus kidney, external Ni2+ stimulated active Na+ uptake via the epithelial Na+ channel, ENaC. Transepithelial capacitance measurements ruled out exocytosis of ENaC-containing vesicles underlying the Ni2+ effect. Na+ current noise analysis was performed using the neutral Na+-channel blocker 6-chloro-3.5-diamino-pyrazine-2-carboxamide (CDPC) and amiloride. The analysis of CDPC-induced noise in terms of a three-state channel model revealed that Ni2+ elicits an increase in the number of open channels as well as in the spontaneous open probability. While Ni2+ had no influence on CDPC-blocker kinetics, the macroscopic and microscopic blocking kinetics of amiloride were affected. Ni2+ turned out to compete with amiloride for a putative binding site but not with CDPC. Moreover, external Na+-known to compete with amiloride and so producing the ``self-inhibition'' phenomenon-and Ni2+ exerted mutually exclusive analogous effects on amiloride kinetics. Na+ current kinetics revealed that Ni2+ prevents ENaC to be downregulated by self-inhibition. Co2+ behaved similarly to Ni2+, whereas Zn2+ did not. Attempts to disclose the chemical nature of the site reacting with Ni2+ suggested cysteine but not histidine as reaction partner.
dc.language.isoen
dc.publisherSPRINGER
dc.relation.ispartofJOURNAL OF MEMBRANE BIOLOGY
dc.subjectA6 cells
dc.subjectALPHA-SUBUNIT
dc.subjectAPICAL MEMBRANE
dc.subjectBiochemistry & Molecular Biology
dc.subjectCell Biology
dc.subjectCHANNEL DENSITY
dc.subjectCHEMICAL-STIMULATION
dc.subjectCONCENTRATION-DEPENDENCE
dc.subjectCURRENT FLUCTUATIONS
dc.subjectENaC
dc.subjectFROG-SKIN
dc.subjectNi2+
dc.subjectnoise analysis
dc.subjectPhysiology
dc.subjectself-inhibition
dc.subjectSODIUM ENTRY
dc.subjectTRANSEPITHELIAL CAPACITANCE
dc.subjectXENOPUS-LAEVIS
dc.titleExternal Ni2+ and ENaC in A6 cells: Na+ current stimulation by competition at a binding site for amiloride and Na+
dc.typejournal article
dc.identifier.doi10.1007/s00232-003-2023-y
dc.identifier.isiISI:000184184200004
dc.description.volume194
dc.description.issue1
dc.description.startpage33
dc.description.endpage45
dc.contributor.orcid0000-0003-1741-3859
dc.contributor.researcheridAAM-5994-2020
dc.contributor.researcheridO-5125-2017
dc.identifier.eissn14321424
dc.publisher.placeONE NEW YORK PLAZA, SUITE 4600, NEW YORK, NY, UNITED STATES
dcterms.isPartOf.abbreviationJ. Membr. Biol.
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