A, ML375 (30 mg/kg) reduces the number of reinforcers earned during cocaine self-administration sessions at the lower doses of cocaine, n=8. B, Response rates (resp/sec) during cocaine self-administration sessions were reduced after treatment with ML375 compared to vehicle. Vehicle pretreatment (black squares), ML375 pretreatment (open squares), 24 hr post ML375 pretreament (gray squares). *( 15 min PT), & (24 hr post inj), p < 0.05.