Intravenous self-administration of fencamfamine and cocaine by beagle dogs under fixed-ratio and progressive-ratio schedules of reinforcement

Catheterized beagle dogs were given access to response-contingent intravenous injections of fencamfamine (FEN) or cocaine (COC) injections under a fixed-ratio (FR) schedule of reinforcement. Both drugs maintained selfadministration behavior considerably above saline levels; there was an inverted U-shaped relationship between the number of injections per daily session and the dose per injection. Presession treatment with the dopaminergic antagonist pimozide (PIM) appreciably altered both the FEN and COC dose-effect curves, suggesting a dopaminergic component in the reinforcing properties of these substances. When tested under a progressive-ratio (PR) schedule, both FEN and COC maintained nearly identical FR-values which were considerably above those seen for saline. It appears from these data that FEN may have a cocaine-like abuse potential.