The central stimulatory action of inhibitors of the dopamine uptake.

The accumulation of ³H-dopamine in cell-free homogenate of mouse forebrain was inhibited by amfonelic acid, mazindol, nomifensine, methylphenidate and (+)-amphetamine. The potency of (+)-amphetamine was strongly (20 times) enhanced by reserpine, whereas that of the other compounds was very slightly influenced. All five compounds produced pronounced hypermotility in mice but only (+)-amphetamine was active in reserpinized mice. The other four compounds antagonized the hyperactivity produced by (+)-amphetamine in the reserpinized mice. The results obtained are in accordance with the view that (+)-amphetamine causes hyperactivity by releasing dopamine, whereas the other compounds act by inhibiting the re-uptake of dopamine.