Synthetic Cathinones and Their Rewarding and Reinforcing Effects in Rodents

Figure 2

The rat intravenous self-administration paradigm for assessment of the abuse liability of synthetic cathinones. Upon pressing of one of two levers (designated the active lever) in an operant self-administration chamber (center), a computer-controlled syringe pump (left) delivers a solution containing MDPV or methylone to an indwelling venous catheter via infusion tubing connected to a liquid swivel. Each drug infusion is accompanied by simultaneous presentation of tone and illumination of a stimulus light located above the lever. Presses on the opposite lever (designated the inactive lever) have no consequences but are recorded to ensure establishment of correct response contingency of drug delivery. The graph on the right represents typical response patterns across daily experimental sessions during the acquisition of drug self-administration.