Changes in rat brain monoamine metabolism following the acute administration of lithium chloride in combination with antidepressant drugs.

The acute administration of lithium chloride resulted in a decrease in the concentration of serotonin, tyrosine, dopamine and noradrenaline in the rat brain. The antidepressant drugs imipramine, amitriptyline and Org GB94 did not reverse or potentiate the effect of lithium chloride on these monoamines or tyrosine. It is concluded that the ability of lithium salts to enhance the effect of antidepressant drugs in the treatment of endogenous depression cannot readily be explained by their synergistic action on brain monoamine metabolism.