Pharmacological changes in dopaminergic systems induced by long-term administration of amantadine.

The pharmacological effects of 6 weeks administration of amantadine was evaluated in the mouse. Motor stimulation induced by amphetamine or the amantadine analog memantine was reduced while that of apomorphine was enhanced by the long-term amantadine treatment. This was accompanied by an increase in the binding of spiroperidol to putative striatal dopamine receptors, without a change in amantadine-induced inhibition of dopamine uptake in the striatum. The possible significance of changes in pre- and postsynaptic dopamine mechanisms is discussed in relation to the anti-parkinson activity of the drug.