Self-administration of amphetamine analogues in rats.

In rats self-injecting amphetamine (0.25 mg/kg/injection) at a stable level during daily 3 hr sessions, three different amphetamine analogues )phenmetrazine, diethylpropion and fenfluramine) were substituted for amphetamine, one at a time on different experimental days. Phenmetrazine (1.0 mg/kg/injection) and diethylpropion (2.0 mg/kg/injection) were self-administered but not fenfluramine (in doses of 0.1, 0.5 and 2.0 mg/kg/injection). It is concluded that amphetamine, phenmetrazine and diethylpropion have reinforcing properties, whereas fenfluramine has not.