Intravenous cocaine-induced place preference: attenuation by haloperidol.

Cocaine reward was demonstrated by establishing a conditioned place preference (CPP) to a distinctive location paired with cocaine administered either intravenously (i.v., 0.5 mg/kg) or intraperitoneally (i.p., 10 mg/kg). Significant i.p. or i.v. cocaine CPP was observed following the second conditioning trial. Haloperidol (0.2 mg/kg) pretreatment disrupted CPP induced by i.v., but not i.p., cocaine. The haloperidol effect built up over successive trials. The involvement of dopaminergic transmission in i.v. cocaine-induced CPP is discussed.