Figure 7.

SB-334867 reduces responding as the unit price of cocaine is increased. (A) Shown are the mean ± SEM percent baseline consumption of cocaine following i.p. injection of vehicle (n = 9) or SB-334867 (7.5, 15, or 30 mg/kg n = 9) on the threshold schedule of reinforcement. (B) Shown are the event records from an individual rat that received an i.p. injection of vehicle or 30 mg/kg SB-334867. Dashed lines denote times in which cocaine doses were reduced every 10 min (for clarity only every other dose is shown). Note that the rate of responding increases as the dose of cocaine is lowered and eventually rats cease responding for cocaine. During the early portions of the session, SB-334867 has no effect on consumption, however, SB-334867 reduced the dose at which rats ceased responding for cocaine. Modified from España et al. (2010).