Place preference conditioning with methylphenidate and nomifensine.

The role of central catecholaminergic systems in place preference conditioning produced by methylphenidate and nomifensine was investigated. Several doses of either methylphenidate or nomifensine produced alterations in place preferences, while desipramine (10 mg/kg), a relatively selective noradrenergic uptake inhibitor, was ineffective, Haloperidol (0.15-0.5 mg/kg) did not attenuate place preferences induced with methylphenidate (2.5 and 5.0 mg/kg) or nomifensine (5.0 mg/kg), although conditioning with methylphenidate (5.0 mg/kg) was blocked after injections of a high dose of haloperidol (1.0 mg/kg). Intraventricular injections of 6-hydroxydopamine had no effect on methylphenidate (2.5 mg/kg) induced place preferences. In contrast, pretreatment with haloperidol (0.2 mg/kg) or intraventricular injections of 6-hydroxydopamine attenuated locomotor activity induced by methylphenidate (5.0 mg/kg). These results suggest that methylphenidate and nomifensine produce place preferences via mechanisms that are either qualitatively or quantitatively distinct from their catecholamine-dependent stimulant actions.