Jones C, Perez E, Amici R, Luppi M, Baracchi F, Cerri M, et al. Lithium affects REM sleep occurrence, autonomic activity and brain second messengers in the rat. Behav Brain Res. 2008;187:254-61 pubmed
..These changes are concomitant with biochemical effects that, in spite of a systemic administration of the substance, may be differentiated according to the second messenger involved, the brain region and the ambient condition. ..