Serum binding, the effect on striatal dopamine release and the metabolism of (-)-deprenyl [N-methyl-N-propargyl(2-phenyl-1-methyl)ethylammonium chloride], TZ-650 [N-methyl-N-propargyl(2-phenyl)ethylammonium chloride] and J-508 [N-methyl-N-propargyl(indanyl)ammonium chloride] were investigated using various chromatographic methods. A strong interaction between (-)-deprenyl and macroglobulins was found. Deprenyl enhanced the dopamine release from striatal slices of the rat brain and also inhibited the dopamine-DOPAC conversion. Deprenyl analogues showed either smaller or no effect. Hydroxylation of (-)-deprenyl takes place in the para position, in addition to the usual oxidative N-dealkylations, which are known from various metabolic studies on N-substituted phenylalkylamines.