title: Effect of direct and indirect dopamine agonists on brain extracellular ascorbate levels in the striatum and nucleus accumbens of awake rats.
abstract: Systemic administration of direct and indirect dopamine agonists resulted in increased extracellular ascorbic acid levels in the striatum and, to a lesser degree, in the nucleus accumbens as measured by in vivo voltammetry. Intraperitoneal d-amphetamine sulfate (5mg/kg) increased ascorbate concentrations in striatal extracellular fluid. Amphetamine also increased extracellular ascorbate levels in the nucleus accumbens although more gradually and to a lesser extent. Intraperitoneal phenethylamine hydrochloride (20 mg/kg) following pargyline hydrochloride pretreatment (20 mg/kg) increased extracellular ascorbate levels in the striatum significantly above the small increase seen in the nucleus accumbens. The direct acting dopamine agonists Ly-141865 and Ly-163502 when given i.p. at 1 mg/kg, resulted in increased extracellular ascorbate concentrations in both brain areas, again with a significantly greater effect in the striatum. These results indicate that brain extracellular ascorbate levels can be modulated by dopaminergic neuro-transmission and that this modulation is quantitatively different in different dopamine-containing brain structures.
authors.affiliation: Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, Indiana 46285.
authors.forename: L A
authors.initials: LA
authors.lastname: Phebus
authors.forename: M E
authors.initials: ME
authors.lastname: Roush
authors.forename: J A
authors.initials: JA
authors.lastname: Clemens
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D003913:Dextroamphetamine / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology*; D004873:Ergolines / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D010627:Phenethylamines / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D015259:Dopamine Agents; D004873:Ergolines; D010627:Phenethylamines; D011804:Quinolines; D019257:Quinpirole; C029261:phenethylamine; D001205:Ascorbic Acid; D003913:Dextroamphetamine; C047726:quinelorane