Effects of norepinephrine and serotonin transporter inhibitors on hyperactivity induced by neonatal 6-hydroxydopamine lesioning in rats

Consistent with their clinical effects in attention deficit-hyper-activity disorder (ADHD), the stimulants methylphenidate and amphetamine reduce motor hyperactivity in juvenile male rats with neonatal 6-hydroxydopamine (6-OHDA) lesions of the forebrain dopamine (DA) system. Since stimulants act on sev-eral aminergic neurotransmission systems, we investigated un-derlying mechanisms involved by comparing behavioral actions of d-methylphenidate, selective inhibitors of the neuronal trans-port of DA [GBR-12909 (1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-[3-phenylpropyl]piperazine dihydrochloride), amfonelic acid], serotonin [5-hydroxytryptamine (5-HT), citalopram, fluvoxam-ine], and norepinephrine (NE; desipramine, nisoxetine) in 6-OHDA lesioned rats. Selective dopamine lesions were made using 6-OHDA (100 g, intracisternal) on postnatal day (PD)