Long-term Effects of Continuous Exposure to Amphetamine on Brain Dopamine Concentration and Synaptosomal Uptake in Mice

Continuous release of p-chloroamphetamine from subcutaneously implanted minipumps for 3 days decreased brain 5-hydroxytryptamine, but not norepinephrine or dopamine, when analyzed 2 weeks later. In contrast, 2 weeks after infusion of amphetamine, whole brain dopamine but not 5-hydroxytryptamine or norepinephrine, was decreased. Also, the high affinity uptake of [3H] dopamine was markedly and selectively reduced in striatal synaptosomes. Thus, neurotoxicity is apparently not unique to halogenated amphetamine derivatives, but is produced by amphetamine itself if administered continuously.