Behavioral supersensitivity to methamphetamine following chronic treatment with (--)-sulpiride in the rat.

Hyperactivity induced by methamphetamine (4 mg/kg i.p.) was actographically evaluated in rats chronically treated with sulpiride stereoisomers and haloperidol. The trial was repeated with half dose of the stimulant after 8 days of neuroleptic withdrawal. (--)-Sulpiride and haloperidol antagonized the response to the full dose of methamphetamine and induced behavioral supersensitivity to the challenging dose. (+)-Sulpiride strongly enhanced the effect of 4 mg/kg of methamphetamine, but no relevant changes in dopaminergic sensitivity followed.