The new aminoadamantane derivative N-(2-adamantyl)hexamethyleneimine hydrochloride (A-7, hemantane) exhibited a pronounced antiparkinsonian effect on various experimental models. Hemantane showed a broad activity spectrum, being superior to amantadine (midantane) in some tests. Administered in an effective antiparkinsonian dose, hemantane increased the extracellular dopamine content in the striatum. The drug also produced a dose-dependent decrease in the extracellular level of dihydroxyphenylacetic acid and homovanillic acid (DOPAC and HVA, the dopamine metabolites) and 5-hydroxyindoloacetic acid (5-HIAc, a serotonin metabolite) in the striatum, which may reflect inhibition of the monoamine oxidase activity in the brain. These results show that the dopaminergic and serotoninergic nigrostriatial systems are involved in the mechanism of hemantane action.