Intravenous self-injection of psychomotor stimulant-anorectics in the baboon

The present study evaluated the intravenous (IV) self-injection of 3 psychomotor stimulant-anorectics in 5 baboons (Papio cynocephalus). A cocaine substitution procedure was used. IV self-injections were available 24 hr/day according to a fixed-ratio (FR) schedule with a 3-hr time-out following each injection. Doses of aminorex (0.01-0.32 mg/kg/injection), propylhexedrine (0.1-3.2 mg/kg/injection), mazindol (0.001-0.1 mg/kg/injection), and their vehicles were substituted for cocaine for 15 or more days. A concurrent FR schedule of food pellet delivery allowed evaluation of changes in food intake. The highest dose of each drug maintained self-injection at rates higher than vehicle control, suppressed food intake, and produced gross behavioral changes similar to those produced by classic psychomotor stimulants such as d-amphetamine. The present data indicate that each of the drugs functions as a positive reinforcer in baboons and suggest that each may have abuse potential.