Antimuscarinic Effects of Lithium

To the Editor: The discovery of the unique action of lithium, a simple monovalent ion, in the therapy of manic-depressive disorders increased interest in the biologic mechanisms underlying the clinical efficacy of lithium as well as its formidable toxicity. The effects of lithium on the biogenic amine system and hormone-stimulated cyclic AMP formation have been extensively examined, whereas its actions on cholinergic neurotransmission remain unexplored. At relatively high concentrations (>10 mM), lithium chloride inhibited the synthesis and release of acetylcholine in presynaptic neurons.¹ However, no decisive biochemical actions of lithium on the postsynaptic neurons have been found. Studying the biochemical…