Effect of lithium on phosphoinositide metabolism in human brain: A proton decoupled P-31 magnetic resonance spectroscopy study

Background: The objective of our study was to evaluate whether lithium incr eases brain phosphomonoester (PME) levels in human subjects. Methods: Proton decoupled P-31 magnetic resonance spectra were obtained fro m eight healthy volunteers before and after the administration of lithium c arbonate, 450 mg b.i.d, for 7 and 14 days. Results: Pairwise comparisons of the mole percent PME revealed a significan t increase from baseline at day 7 and day 14 of lithium administration. Conclusions: An increase in PME concentration with 7 and 14 days of lithium administration in the human brain in vivo was observed. Because the inosit ol-1-monophosphate contributes to the PME peak, this result suggests that s ome of the initial actions of lithium may occur through a reduction of myo- inositol, which in turn may initiate a cascade of secondary changes at diff erent levels of signal transduction process and gene expression in brain, e ffects that are ultimately responsible for the therapeutic benefits of lith ium. Biol Psychiatry 2001;50: 3-7 (C) 2001 Society of Biological Psychiatry .