Serotonin depletion induced by reserpine is attenuated by prophylactic administration of lithium.

Prophylactic administration of lithium significantly attenuated the serotonin depleting effects of reserpine. In rat brain, lithium did not change the capacity of the storage protein, serotonin binding protein to bind the amine either in vivo or in vitro nor did it change its sensitivity to reserpine. However, the chronic administration of lithium significantly decreased reserpine levels in plasma and brain tissue of treated rats compared with rats which were treated only with reserpine. It is concluded that the antagonism between reserpine and lithium does not involve the serotonin binding protein but may be due to the lithium-induced reduction of reserpine levels.