Effect of lithium on phosphoinositide metabolism in human brain: a proton decoupled (31)P magnetic resonance spectroscopy study

The objective of our study was to evaluate whether lithium increases brain phosphomonoester (PME) levels in human subjects.

Proton decoupled (31)P magnetic resonance spectra were obtained from eight healthy volunteers before and after the administration of lithium carbonate, 450 mg b.i.d., for 7 and 14 days.

Pairwise comparisons of the mole percent PME revealed a significant increase from baseline at day 7 and day 14 of lithium administration.

An increase in PME concentration with 7 and 14 days of lithium administration in the human brain in vivo was observed. Because the inositol-1-monophosphate contributes to the PME peak, this result suggests that some 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 different levels of signal transduction process and gene expression in brain, effects that are ultimately responsible for the therapeutic benefits of lithium.