2018
Modulations in extracellular calcium lead to H+-ATPase-dependent acid secretion: a clarification of PPI failure
Kitay AM, Schneebacher MT, Schmitt A, Heschl K, Kopic S, Alfadda T, Alsaihati A, Link A, Geibel J. Modulations in extracellular calcium lead to H+-ATPase-dependent acid secretion: a clarification of PPI failure. AJP Gastrointestinal And Liver Physiology 2018, 315: g36-g42. PMID: 29517927, DOI: 10.1152/ajpgi.00132.2017.Peer-Reviewed Original ResearchConceptsAcid secretionParietal cellsExtracellular calciumGastric parietal cellsProton pump inhibitor exposureExtracellular CaPotassium-free conditionsRecurrent reflux symptomsCalcium sensing receptorGastric acid secretionPPI failurePPI therapyReflux symptomsIsolated gastric glandsInhibitor exposureCalcimimetic R568Pharmacological targetsSensing receptorAbsence of sodiumCalcium concentrationCaSRGastric glandsSecretionATPase activityExcretion pathway
2013
Activation of AMPK Inhibits Cholera Toxin Stimulated Chloride Secretion in Human and Murine Intestine
Rogers AC, Huetter L, Hoekstra N, Collins D, Collaco A, Baird AW, Winter DC, Ameen N, Geibel JP, Kopic S. Activation of AMPK Inhibits Cholera Toxin Stimulated Chloride Secretion in Human and Murine Intestine. PLOS ONE 2013, 8: e69050. PMID: 23935921, PMCID: PMC3728293, DOI: 10.1371/journal.pone.0069050.Peer-Reviewed Original ResearchConceptsIntestinal chloride secretionCholera toxinChloride secretionPharmacological activationFluid accumulationColonic cryptsSupplemental treatment strategyAcute diarrheal illnessChloride effluxCystic fibrosis transmembrane conductance regulatorExcised intestinal segmentsRat colonic cryptsMurine colonic mucosaMucosal sheetsDiarrheal illnessIntestinal loopsEnterotoxigenic diarrheaColonic mucosaTreatment strategiesIntestinal segmentsUssing chambersAMPK activator AICARMurine intestineTissue levelsMetformin
2009
AMP-activated protein kinase: a physiological off switch for murine gastric acid secretion
Sidani S, Kopic S, Socrates T, Kirchhoff P, Föller M, Murek M, Capasso A, Geibel JP. AMP-activated protein kinase: a physiological off switch for murine gastric acid secretion. Pflügers Archiv - European Journal Of Physiology 2009, 459: 39. PMID: 19621238, DOI: 10.1007/s00424-009-0698-3.Peer-Reviewed Original ResearchConceptsProtein kinaseAMPK activationSecretagogue-induced acid secretionCellular ATP levelsPresence of AMPKEnergy-dependent transportersImmunofluorescent localizationParietal cellsGastric glandsCellular ATP consumptionGastric parietal cellsCompound CAMPKProton effluxATP consumptionMetabolic stressRate of intracellularATP levelsKinaseAdenosine monophosphateRegulatorATPLarge abundanceCellsActivation
2007
Stimulatory Pathways of the Calcium-Sensing Receptor on Acid Secretion in Freshly Isolated Human Gastric Glands
Remy C, Kirchhoff P, Hafner P, Busque S, Mueller M, Geibel J, Wagner C. Stimulatory Pathways of the Calcium-Sensing Receptor on Acid Secretion in Freshly Isolated Human Gastric Glands. Cellular Physiology And Biochemistry 2007, 19: 33-42. PMID: 17310098, DOI: 10.1159/000099190.Peer-Reviewed Original ResearchConceptsHeterotrimeric G proteinsHuman gastric glandsMAP kinaseGastric parietal cellsATPase activityG proteinsGastric acid secretionERK 1/2 MAP kinaseIndependent PKC isoformsStimulation of CaSRERK1/2 MAP kinasesAcid secretionProtein kinase CPKC-delta isoformParietal cellsStimulatory effectChelator of intracellularActivation of PKCGastric glandsHuman gastric parietal cellsPLC inhibitor U73122Sensitive heterotrimeric G proteinsPD 098059General inhibitorPKC isoforms
2006
Somatostatin modulates PI3K-Akt, eNOS and NHE activity in the ciliary epithelium
Ghosh S, Choritz L, Geibel J, Coca-Prados M. Somatostatin modulates PI3K-Akt, eNOS and NHE activity in the ciliary epithelium. Molecular And Cellular Endocrinology 2006, 253: 63-75. PMID: 16764985, DOI: 10.1016/j.mce.2006.05.002.Peer-Reviewed Original ResearchConceptsP-Akt Ser473Ciliary epitheliumIntracellular cyclic GMP productionInvolvement of somatostatinDose-dependent attenuationReceptor mRNA expressionCyclic GMP productionSST-like immunoreactivityLack of responseOcular ciliary epitheliumAqueous humorSomatostatinNHE activityExchanger activityMRNA expressionCiliary processesNeuroendocrine cellsPC2 antibodyPI3K-AktMultiple intracellularGMP productionConvertases PC1Increases phosphorylationTissue extractsEpitheliumAn update on acid secretion
Geibel JP, Wagner C. An update on acid secretion. Reviews Of Physiology, Biochemistry And Pharmacology 2006, 156: 45-60. PMID: 16634146, DOI: 10.1007/s10254-005-0003-0.Peer-Reviewed Original ResearchConceptsApical proteinsSecretory pathwayRegulatory mechanismsTransporter proteinsCalcium-sensing receptor activationParietal cellsApical surfaceCalcium-sensing receptorComplex processParietal cell canaliculiAcid productionProteinApical channelsReceptor activationInsertion of pumpsPathwayCellsActivationRecent candidateSecretion of acidSecretionReceptorsAcid secretionCatalytic cycleATPase
1998
Angiotensin II stimulates vesicular H+-ATPase in rat proximal tubular cells
Wagner C, Giebisch G, Lang F, Geibel J. Angiotensin II stimulates vesicular H+-ATPase in rat proximal tubular cells. Proceedings Of The National Academy Of Sciences Of The United States Of America 1998, 95: 9665-9668. PMID: 9689138, PMCID: PMC21396, DOI: 10.1073/pnas.95.16.9665.Peer-Reviewed Original ResearchConceptsAngiotensin IIProximal tubulesIon secretionEffect of AIIRat proximal tubular cellsAngiotensin II stimulatesRemoval of ClPH-sensitive fluorescent dye 2Proximal tubular cellsNa/H exchangerBafilomycin A1Proximal tubule fragmentsTubular cellsBicarbonate reabsorptionHCO3- reabsorptionTubule fragmentsH exchangerATPase activityFluorescent dye 2Proton pump inhibitor bafilomycin A1Intracellular pHTubulesSecretionPresent studyCell pH