2013
Identification of Functionally Distinct Na-HCO3 Co-Transporters in Colon
Barmeyer C, Ye JH, Soroka C, Geibel P, Hingsammer LM, Weitgasser L, Atway D, Geibel JP, Binder HJ, Rajendran VM. Identification of Functionally Distinct Na-HCO3 Co-Transporters in Colon. PLOS ONE 2013, 8: e62864. PMID: 23690961, PMCID: PMC3653958, DOI: 10.1371/journal.pone.0062864.Peer-Reviewed Original ResearchConceptsNa-HCO3 cotransportDistal colonProximal colonNBC activityNBC isoformsRat colonColonic epithelial cellsCrypt glandsSensitive transporterHCO3- secretionColonHCO3-dependent mechanismEpithelial cellsSaturable processHOE694Isoform 1Basolateral membraneCotransportPCR analysisNorthern blotDIDSMolecular studiesMolecular identityApparent KiCritical role
2011
Functional role of NHE4 as a pH regulator in rat and human colonic crypts
Arena EA, Longo WE, Roberts KE, Geibel P, Nateqi J, Brandstetter M, Geibel JP. Functional role of NHE4 as a pH regulator in rat and human colonic crypts. American Journal Of Physiology - Cell Physiology 2011, 302: c412-c418. PMID: 22049213, DOI: 10.1152/ajpcell.00163.2011.Peer-Reviewed Original ResearchConceptsHuman colonic cryptsNHE4 activityColonic cryptsElective colon resectionEffects of aldosteroneSprague-Dawley ratsColon resectionRat modelGastrointestinal tractAldosteroneColonic samplesΜM forskolinFluid homeostasisRatsHuman colonHuman specimensCAMP levelsIntracellular pathwaysCryptsNHE4ColonSignificant changesLittle descriptionFunctional roleRecent studies
2007
Characteristics of rat downregulated in adenoma (rDRA) expressed in HEK 293 cells
Barmeyer C, Ye JH, Sidani S, Geibel J, Binder HJ, Rajendran VM. Characteristics of rat downregulated in adenoma (rDRA) expressed in HEK 293 cells. Pflügers Archiv - European Journal Of Physiology 2007, 454: 441-450. PMID: 17492310, DOI: 10.1007/s00424-007-0213-7.Peer-Reviewed Original ResearchMeSH Keywords4,4'-Diisothiocyanostilbene-2,2'-Disulfonic AcidAmino Acid SequenceAnimalsAntiportersBase SequenceBicarbonatesCell LineChloridesCloning, MolecularColonDNA PrimersFatty Acids, VolatileHumansHydrogen-Ion ConcentrationIon TransportMolecular Sequence DataRatsRecombinant ProteinsSequence Homology, Amino AcidSulfate TransportersTransfectionConceptsRat distal colonDistal colonHEK-293 cellsExtracellular Cl- concentrationCrypt cellsMRNA expressionColonRatsDigestive tractCharacteristics of ratsAdenomasHigh rateDIDSCl- influxSurface cellsIntracellular acidApical membrane vesiclesCellsDisulfonic acidApical membraneCl- uptakePrior observationsUptakeLungJejunum
2005
Bicarbonate Secretion
Binder HJ, Rajendran V, Sadasivan V, Geibel JP. Bicarbonate Secretion. Journal Of Clinical Gastroenterology 2005, 39: s53-s58. PMID: 15758660, DOI: 10.1097/01.mcg.0000155521.81382.3a.Peer-Reviewed Original ResearchSECRETION AND ABSORPTION BY COLONIC CRYPTS
Geibel JP. SECRETION AND ABSORPTION BY COLONIC CRYPTS. Annual Review Of Physiology 2005, 67: 471-490. PMID: 15709966, DOI: 10.1146/annurev.physiol.67.031103.153530.Peer-Reviewed Original Research
2003
Characterization of Cl-HCO3 exchange in basolateral membrane of rat distal colon
Ikuma M, Geibel J, Binder HJ, Rajendran VM. Characterization of Cl-HCO3 exchange in basolateral membrane of rat distal colon. American Journal Of Physiology - Cell Physiology 2003, 285: c912-c921. PMID: 12826602, DOI: 10.1152/ajpcell.00396.2002.Peer-Reviewed Original ResearchConceptsRat distal colonCl-HCO3 exchangeDistal colonBasolateral membraneHalf-maximal inhibitory constantsBasolateral membrane vesiclesCl- channel blockerColonic epithelial cellsAbsence of HCO3Channel blockersRat colonic epithelial cellsCrypt preparationCrypt cellsExchange inhibitorCl-OH exchangeRemoval of ClColonEpithelial cellsAnion exchange inhibitorHCO3- gradientProtease inhibitorsK ionophorePresent studyInhibitory constantsProtease inhibitor cocktailNa-H Exchange Function in Colonic Epithelial Cells
Binder H, Rajendran V, Geibel J. Na-H Exchange Function in Colonic Epithelial Cells. 2003, 71-90. DOI: 10.1007/978-1-4615-0427-6_5.Peer-Reviewed Original ResearchColonic epithelial cellsShort-chain fatty acidsEpithelial cellsSmall intestinal epithelial cellsAbsorption of carbohydratesIntestinal epithelial cellsSecretion of fluidEpithelial cell functionNeonatal periodCrypt cellsDistal segmentsCell functionSignificant heterogeneityMammalian colonSecretory processColonFatty acidsCl transportMultiple factorsCellsNutrient absorptionExchange functionHormoneSecretion
2001
Characterization of apical membrane Cl-dependent Na/H exchange in crypt cells of rat distal colon
Rajendran V, Geibel J, Binder H. Characterization of apical membrane Cl-dependent Na/H exchange in crypt cells of rat distal colon. AJP Gastrointestinal And Liver Physiology 2001, 280: g400-g405. PMID: 11171622, DOI: 10.1152/ajpgi.2001.280.3.g400.Peer-Reviewed Original ResearchConceptsRat distal colonNa/H exchangeCl- channel blockerDistal colonChannel blockersCrypt cellsIntracellular pH recoveryExchange inhibitor amilorideColonic epithelial cellsApical membrane vesiclesCrypt glandsHigh doseHOE 694NA depletionAcid loadExchange inhibitorInhibitor amiloridePH recoveryEpithelial cellsUptake 1NHE isoformsAnion exchange inhibitorBlockersColonNa uptake
1998
Cl−HCO3 and Cl−OH exchanges of basolateral membranes (BLM) regulate intracellular pH (pHi) in crypt cells of rat distal colon
Ikuma M, Geibel J, Binder H, Rajendran V. Cl−HCO3 and Cl−OH exchanges of basolateral membranes (BLM) regulate intracellular pH (pHi) in crypt cells of rat distal colon. Gastroenterology 1998, 114: a380. DOI: 10.1016/s0016-5085(98)81539-4.Peer-Reviewed Original ResearchDifferential localization of colonic H+-K+-ATPase isoforms in surface and crypt cells
Rajendran V, Singh S, Geibel J, Binder H. Differential localization of colonic H+-K+-ATPase isoforms in surface and crypt cells. American Journal Of Physiology 1998, 274: g424-g429. PMID: 9486199, DOI: 10.1152/ajpgi.1998.274.2.g424.Peer-Reviewed Original ResearchConceptsCrypt cellsColonic cryptsRat distal colonSurface cellsSurface epithelial cellsATPase isoformsOuabain-insensitive componentApical membraneDistal colonAcid loadDependent intracellularEpithelial cellsATPase activityCryptsDifferential localizationOuabainATPase alpha subunitCellsAlpha subunitCompelling evidenceIsoformsColonActivityRecovery
1995
Chloride-dependent Na-H Exchange A NOVEL MECHANISM OF SODIUM TRANSPORT IN COLONIC CRYPTS*
Rajendran V, Geibel J, Binder H. Chloride-dependent Na-H Exchange A NOVEL MECHANISM OF SODIUM TRANSPORT IN COLONIC CRYPTS*. Journal Of Biological Chemistry 1995, 270: 11051-11054. PMID: 7744735, DOI: 10.1074/jbc.270.19.11051.Peer-Reviewed Original ResearchConceptsNa-H exchangeColonic crypt cellsCrypt cellsAcid loadRat distal colonApical membrane vesiclesNovel transport processRate of intracellularDistal colonMM amilorideSodium transportApical membraneGradient stimulationColonic cryptsAmiloride inhibitionSodium movementNovel mechanismOutward gradientCompelling evidenceCellsSodiumUptakePrior studiesColonRecovery