Chronic l-dopa fails to lessen rebound enhancement of self-stimulation after chronic haloperidol.

Chronic treatment with haloperidol (approximately 4.8 mg/rat/day PO for 18 days) severely impaired variable-interval hypothalamic self-stimulation. Cessation of treatment was followed by a strong rebound increase in response rates at submaximal currents, to well above pretreatment rates. The rebound increase in responding was not prevented (and at submaximal currents was actually enhanced) by treatment with l-dopa plus benserazide (respectively 240 and 60 mg/kg/day PO) for 6 days after withdrawal of haloperidol. This result is at variance with previously reported findings.