Effect of chronic Li+ treatment on free intracellular Mg2+ in human neuroblastoma SH-SY5Y cells.

Abstract

OBJECTIVES:

Previous findings have demonstrated Li+/Mg2+ competition at therapeutic intracellular Li+ levels after acute Li+ treatment in human neuroblastoma SH-SY5Y cells. In the current study, we examined whether Li+/Mg2+ competition exists at therapeutically relevant extra- and intracellular [Li+] after chronic Li+ loading times.

METHODS:

In human neuroblastoma cells, intracellular free Mg2+ was determined by fluorescence spectroscopy with the fluorophore furaptra. Intracellular Li+ and Mg2+ were measured by atomic absorption spectrophotometry.

RESULTS:

After loading of the neuroblastoma cells with 1-2 mM extracellular Li+ for 24-72 h, the observed, increased intracellular free [Mg2+] levels were significantly higher (p < 0.03) than those in matched Li+ free cells, and intracellular [Li+] was found to be at therapeutic intracellular levels (0.7-1.5 mM).

CONCLUSIONS:

The results demonstrate that Li+/Mg2+ competition exists after chronic treatment with Li+ at therapeutically relevant intracellular Li+ levels in neuroblastoma cells. We found differences between acute and chronic Li+ treatment effects on the extent of Li+/Mg2+ competition. Possible reasons for these differences are discussed.

• Authors: Abde M Abukhdeir, Brian T Layden, Nicole Minadeo, Fred B Bryant, Evan B Stubbs Jr, Duarte Mota de Freitas
• Journal: Bipolar disorders (Bipolar Disord) Vol. 5 Issue 1 Pg. 6-13 (Feb 2003) ISSN: 1398-5647 [Print] Denmark
• PMID: 12656932 (Publication Type: Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Lithium
• Magnesium

Topics

• Analysis of Variance
• Bipolar Disorder (drug therapy, metabolism)
• Dose-Response Relationship, Drug
• Humans
• Intracellular Fluid (chemistry)
• Ion Transport (drug effects)
• Lithium (analysis, pharmacology)
• Magnesium (analysis, metabolism)
• Neuroblastoma
• Tumor Cells, Cultured