Opposite effects of sulpiride and SCH 23390 on ethanol-induced striatal ascorbic acid release in intact and 6-hydroxydopamine lesioned rats.
The effects of L-sulpiride and SCH 23390 on ethanol-induced striatal ascorbic acid (AA) release in normal and 6-hydroxydopamine-lesioned rats were studied by using microdialysis coupled to high performance liquid chromatography with electrochemical detection. Ethanol (3.0 g/kg i.p.) significantly stimulated striatal AA release by 200% above the baseline in normal, 6-hydroxydopamine-lesioned, and reserpine-treated rats. L-Sulpiride, a dopamine D(2) antagonist, at the dose of 100 mg/kg i.p., decreased basal ascorbic acid release and showed an inhibitory tendency on ethanol-induced ascorbic acid release. However, at the higher dose of 200 mg/kg i.p., L-sulpiride significantly inhibited ethanol-induced ascorbic acid release in both normal and 6-hydroxydopamine-treated rats. SCH 23390, a dopamine D(1) antagonist, at the doses of 0.5 and 1.0 mg/kg i.p., potentiated ethanol-induced ascorbic acid release in normal rats. However, the potentiation of SCH 23390 on ethanol effect was not significant in 6-hydroxydopamine-treated rats at the dose of 1.0 mg/kg i.p. The present study demonstrates that opposite actions exist in the regulation of ethanol-induced ascorbic acid release in the striatum by dopamine D(1) and D(2) receptor blockade. It also suggests that the postsynaptic dopamine receptors are involved in mediation of ethanol-induced ascorbic acid release in rat striatum.
Liu
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Department of Pharmacology of Chinese Materia Medica, Shenyang Pharmaceutical University, 103 Wenhua Road, 110015, Shenyang, PR China.
Wu
C F
CF
Huang
M
M
Xiao
K
K
D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D001552:Benzazepines / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism; D018492:Dopamine Antagonists / Q000494:pharmacology; D000431:Ethanol / Q000009:adverse effects*; D005260:Female; D017072:Neostriatum / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012110:Reserpine / Q000494:pharmacology; D013378:Substantia Nigra / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013469:Sulpiride / Q000494:pharmacology*
D001552:Benzazepines; D018492:Dopamine Antagonists; D000431:Ethanol; D013469:Sulpiride; D012110:Reserpine; D001205:Ascorbic Acid; D004298:Dopamine