Lithium slows neuronal calcium regulation in the snail Helix pomatia.

Steady-state and transient changes in intracellular calcium concentrations ([Ca2+]i) of snail neurons (Helix pomatia) were measured by the Ca2+ indicator Arsenazo(III) following manipulation of the extracellular concentration of lithium chloride (LiCl). Application of LiCl in concentrations equivalent to those used in the treatment of manic-depressive illness produces slowing in Ca2+ reequilibration after Ca2+-influx during depolarization, concomitantly with steady-state elevation of [Ca2+]i of about 100 nM, suggesting a change in Ca2+ reequilibration as a prominent action of LiCl. This mechanism may be relevant to the therapeutic effects of LiCl.