title: Cortical ablation and drug-induced changes in striatal ascorbic acid oxidation and behavior in the rat.
abstract: Rats whose frontoparietal cortex had been bilaterally ablated were allowed 21 days for recovery and then treated with apomorphine (APO), 1 mg/kg SC or scopolamine (SCOP), 0.6 mg/kg SC. Soon after a behavioral test, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbic acid (AA), and dehydroascorbic acid (DHAA) levels were determined by HPLC/EC in striatal synaptosomes (left side) and whole striatum (right side). SCOP behavioural effects were attenuated by cortical ablation, while those of APO were affected to a lesser extent. In the striatum of unoperated and sham-operated rats DHAA contents and DHAA/AA ratio resulted increased after drugs administration. No change in AA oxidation was observed in the striatum of ablated rats. In the synaptosomes of unoperated and sham-operated rats both drugs led to a decrease in DHAA contents and DHAA/AA ratio. In unoperated and sham-operated rats APO and SCOP caused a decrease of the DOPAC/DA ratio in the whole striatum and striatal synaptosomes. In ablated rats APO caused a decrease of DOPAC/DA ratio in the whole striatum and synaptosomes, while SCOP effects on DA turnover resulted attenuated in the whole striatum and abolished in synaptosomes. We conclude that drug-induced AA oxidation is likely to occur in the extracellular space and requires intact corticostriatal glutamatergic pathways. The latter may play an enabling role in SCOP behavioral effects.
authors.affiliation: Institute of Pharmacology, University of Sassari, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Miele
authors.forename: P
authors.initials: P
authors.lastname: Enrico
authors.forename: G
authors.initials: G
authors.lastname: Esposito
authors.forename: L
authors.initials: L
authors.lastname: Fresu
authors.forename: R
authors.initials: R
authors.lastname: Migheli
authors.forename: G
authors.initials: G
authors.lastname: De Natale
authors.forename: M S
authors.initials: MS
authors.lastname: Desole
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001205:Ascorbic Acid / Q000378:metabolism*; D001522:Behavior, Animal / Q000187:drug effects*; D002540:Cerebral Cortex / Q000502:physiology*; D003683:Dehydroascorbic Acid / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D012601:Scopolamine / Q000494:pharmacology; D013239:Stereotyped Behavior / Q000187:drug effects; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism
chemical_list: D015102:3,4-Dihydroxyphenylacetic Acid; D018698:Glutamic Acid; D012601:Scopolamine; D001058:Apomorphine; D001205:Ascorbic Acid; D004298:Dopamine; D003683:Dehydroascorbic Acid