Effects of Dopamine Antagonists on Neuronal Histamine Release in the Striatum of Rats Subjected to Acute and

In this study, we examined the changes in neuronal histamine (HA) release in the rat striatum after acute and repeated admin-istration of methamphetamine (METH). We studied the regula-tion of METH-induced HA release by dopamine receptors and the relationship between METH-induced HA release and ste-reotyped behavior. Acute administration of METH (1 mg/kg) significantly increased HA release 60 mm later. Pretreatments with the dopamine D2 antagonists sulpiride and haloperidol blocked the METH-induced increase of HA release, whereas pretreatment with a dopamine D1 antagonist, SCH23390, did not. Moreover, repeated administration of METH (3 mg/kg) greatly enhanced the METH-induced increase of HA release 60, 80, 1 00, 120 and 1 80 mm after rechallenge of METH (1 mg/kg). Repeated treatment with haloperidol and METH blocked th