In vivo 7Li NMR diffusion studies in rat brain

Lithium (Li) is widely used for the treatment of several psychiatric disorders and is the drug of choice in the treatment of bipolar disorders. The mechanism of action of Li, however, is unknown. A knowledge of brain Li concentration, its distribution in the brain, and its properties in the cellular microenvironments may contribute significantly towards the understanding of its function. We recently demonstrated by in vivo 7Li NMR the distribution and pharmacokinetics of Li ion in rat brain. We have made diffusion measurements of Li in the head and brain regions of anesthetized rats using the localized STEAM (stimulated echo acquisition mode spectroscopy) technique suitably sensitized to diffusion. In this paper we demonstrate for the first time the feasibility of Li diffusion measurements in the mammalian brain model with the ultimate goal of performing such studies on humans under Li therapy.