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Li + /Mg 2+ competition at therapeutic intracellular Li + levels in human neuroblastoma SH‐SY5Y cells
Author(s) -
Layden Brian,
Diven Conrad,
Minadeo Nicole,
Bryant Fred B,
Mota de Freitas Duarte
Publication year - 2000
Publication title -
bipolar disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.285
H-Index - 129
eISSN - 1399-5618
pISSN - 1398-5647
DOI - 10.1034/j.1399-5618.2000.020308.x
Subject(s) - intracellular , neuroblastoma , sh sy5y , incubation , chemistry , lithium (medication) , intracellular ph , lithium therapy , absorption (acoustics) , biophysics , microbiology and biotechnology , analytical chemistry (journal) , cell culture , biology , biochemistry , endocrinology , materials science , chromatography , bipolar disorder , genetics , composite material
Objectives:One proposed mechanism of lithium action in the treatment of bipolar disorder is that Li + competes with Mg 2+ for Mg 2+ binding sites within the cell. In this study, we investigated this competition at therapeutic intracellular Li + levels in human neuroblastoma SH‐SY5Y cells.
Methods: We used fluorescence spectroscopy and a Mg 2+ indicator, furaptra, to investigate this competition in human neuroblastoma SH‐SY5Y cells. Atomic absorption spectrophotometry was used for determination of the intracellular Li + levels.
Results: The neuroblastoma cells, incubated in 15 mM or 30 mM Li + ‐containing buffer, showed a significant increase in free intracellular Mg 2+ levels [using a positive linear within‐groups contrast t ‐test, the 15 mM condition produced t(2)=5.0, one‐tailed p<0.02, and the 30 mM Li + ‐incubation conditions gave t(2)=9.2, one‐tailed p<0.006] but did not significantly increase over time in the Li + ‐free condition [t(2)=0.1, one‐tailed p>0.96]. At the earlier times during the incubation (1 or 10 min for the 15 mM or 30 mM Li + ‐containing buffers), the intracellular Li + concentrations were 0.6–2.5 mM, values which are comparable to those reached in the brain of Li + ‐treated patients.
Conclusion: We demonstrated that competition between Li + and Mg 2+ can occur at therapeutic intracellular Li + levels.