title: Single administration of 1-benzyl-1,2,3,4-tetrahydroisoquinoline increases the extracellular concentration of dopamine in rat striatum.
abstract: We performed a combined neurochemical and behavioral study to determine the effects of 1-benzyl-1,2,3,4-tetrahydroisoquinoline (1-BnTIQ) on the extracellular dopamine concentrations in the striatum. Single dose administration of 1-BnTIQ (20, 40, and 80 mg/kg i.p.) increased striatal dopamine extracellular levels in a dose-dependent manner when an in vivo microdialysis technique was used to assess dopamine levels in the striatum of rats. Enhancement of striatal dopamine levels by systemic administration of a single dose of 1-BnTIQ was suppressed by perfusion of tetrodotoxin and a calcium ion-free solution into the striatum. This 1-BnTIQ-induced increase in extracellular dopamine concentration was also inhibited by pre-treatment with a dopamine uptake inhibitor, GBR12909 (1-(2-[bis(4-Fluorophenyl)-4-(3-phenylpropyl)piperazine dihydrochloride). Local application of 1-BnTIQ into the striatum via a dialysis probe failed to enhance the extracellular concentration of dopamine. However, microinjection of 1-BnTIQ into the substantia nigra pars compacta increased the extracellular dopamine levels in the striatum. Locomotor activity was increased by systemic administration of a single dose of 1-BnTIQ in a dose-dependent manner. This 1-BnTIQ-induced locomotor activity was attenuated by pre-treatment with SCH23390 (R(+)-7-Chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochlodride) and raclopride, D(1) and D(2) dopaminergic receptor antagonists, respectively. Moreover, 1-BnTIQ induced ipsilateral rotational behavior in 6-hydroxydopamine-lesioned rats. These results suggest that systemic administration of a single dose of 1-BnTIQ increases striatal extracellular dopamine concentration through activation of dopaminergic nigra striatal neurons via the dopamine transporter.
authors.affiliation: Department of Pharmacotherapeutics, Showa Pharmaceutical University, 3-3165 Higashitamagawagakuen, Machida, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Katagiri
authors.forename: K
authors.initials: K
authors.lastname: Abe
authors.forename: M
authors.initials: M
authors.lastname: Kitabatake
authors.forename: I
authors.initials: I
authors.lastname: Utsunomiya
authors.forename: Y
authors.initials: Y
authors.lastname: Horiguchi
authors.forename: K
authors.initials: K
authors.lastname: Hoshi
authors.forename: K
authors.initials: K
authors.lastname: Taguchi
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology; D050483:Dopamine Plasma Membrane Transport Proteins / Q000187:drug effects / Q000378:metabolism; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D045604:Extracellular Fluid / Q000187:drug effects / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D016627:Oxidopamine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism; D013565:Sympatholytics; D044005:Tetrahydroisoquinolines / Q000494:pharmacology*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D018492:Dopamine Antagonists; D050483:Dopamine Plasma Membrane Transport Proteins; D018765:Dopamine Uptake Inhibitors; D026941:Sodium Channel Blockers; D013565:Sympatholytics; D044005:Tetrahydroisoquinolines; D013779:Tetrodotoxin; D016627:Oxidopamine; D004298:Dopamine; C084924:1,2,3,4-tetrahydro-1-(phenylmethyl)isoquinoline