title: Inhibition of dopamine synthesis with alpha-methyl-p-tyrosine abolishes the enhancement of methamphetamine-induced extracellular dopamine levels in the amygdala of rats with excitotoxic lesions of the entorhinal cortex.
abstract: This study was performed to investigate the mechanisms underlying the augmentation of methamphetamine (MAP)-induced dopamine (DA) release in the entorhinal cortex-lesioned rats. Quinolinic acid or phosphate buffered saline was infused into the left entorhinal cortex of adolescent rats (postnatal day 7 weeks). After 4 weeks of lesioning, acute MAP (2 mg/kg, i.p.)-induced DA release in the amygdala was significantly enhanced in lesioned rats compared to sham operated rats. Inhibition of DA synthesis by alpha-methyl-p-tyrosine, an inhibitor of catecholamine synthesis, resulted in abolishment of the enhancement of MAP (2 or 5 mg/kg, i.p.)-induced DA release in the amygdala of lesioned rats. These results suggest that excessive DA pool in nerve terminals underlies the augmentation of MAP-induced DA release in the amygdala of the lesioned rats.
authors.affiliation: Department of Neuropsychiatry, Faculty of Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, Japan. uehara@ms.toyama-mpu.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Uehara
authors.forename: Tomiki
authors.initials: T
authors.lastname: Sumiyoshi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Itoh
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kurachi
mesh_terms: D000679:Amygdala / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D004298:Dopamine / Q000096:biosynthesis*; D018728:Entorhinal Cortex / Q000187:drug effects* / Q000378:metabolism; D045604:Extracellular Fluid / Q000187:drug effects / Q000502:physiology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D017378:Quinolinic Acid / Q000633:toxicity; D051381:Rats; D017208:Rats, Wistar; D019805:alpha-Methyltyrosine / Q000494:pharmacology*
chemical_list: D008694:Methamphetamine; D019805:alpha-Methyltyrosine; D017378:Quinolinic Acid; D004298:Dopamine