title: 7Li nuclear magnetic resonance study for the determination of Li+ properties in neuroblastoma SH-SY5Y cells.
abstract: Lithium has been used clinically in the treatment of manic depression. However, its pharmacologic mode of action remains unclear. Characteristics of Li+ interactions in red blood cells (RBCs) have been identified. We investigated Li+ interactions on human neuroblastoma SH-SY5Y cells by developing a novel 7Li NMR method that provided a clear estimation of the intra- and extracellular amounts of Li+ in the presence of the shift reagent thulium-1,4,7,10-tetrazacyclododecane-N,N',N'',N'''-tetramethylene phosphonate (HTmDOTP4-). The first-order rate constants of Li+ influx and efflux for perfused, agarose-embedded SH-SY5Y cells in the presence of 3 mM HTmDOTP4- were 0.055 +/- 0.006 (n = 4) and -0.025 +/- 0.006 min(-1) (n = 3), respectively. Significant increases in the rate constants of Li+ influx and efflux in the presence of 0.05 mM veratridine indicated the presence of Na+ channel-mediated Li+ transport in SH-SY5Y cells. 7Li NMR relaxation measurements showed that Li+ is immobilized more in human neuroblastoma SH-SY5Y cells than in human RBCs.
authors.affiliation: Department of Chemistry, Loyola University Chicago, Illinois 60626, USA.
authors.forename: J
authors.initials: J
authors.lastname: Nikolakopoulos
authors.forename: C
authors.initials: C
authors.lastname: Zachariah
authors.forename: D
authors.initials: D
authors.lastname: Mota de Freitas
authors.forename: E B
authors.initials: EB
authors.lastname: Stubbs
authors.forename: R
authors.initials: R
authors.lastname: Ramasamy
authors.forename: M C
authors.initials: MC
authors.lastname: Castro
authors.forename: C F
authors.initials: CF
authors.lastname: Geraldes
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D007424:Intracellular Fluid / Q000737:chemistry / Q000378:metabolism; D017136:Ion Transport / Q000187:drug effects; D007554:Isotopes; D008094:Lithium / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D009447:Neuroblastoma / Q000737:chemistry* / Q000378:metabolism* / Q000473:pathology; D010042:Ouabain / Q000494:pharmacology; D010477:Perfusion; D010693:Phloretin / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014701:Veratridine / Q000494:pharmacology
chemical_list: D007554:Isotopes; D010042:Ouabain; D014701:Veratridine; D008094:Lithium; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D010693:Phloretin