Effects of D1 and D2 antagonists on the transient increase of dopamine release by dopamine agonists by means of brain dialysis.
The effects of selective D1 and D2 antagonists, R-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepine-7- ol(SCH-23390) and sulpiride, on the transient increase of dopamine (DA) release induced by DA agonists, apomorphine (APO) and 2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine (SKF-38393) were examined in the caudate-putamen of freely moving rat by means of microdialysis during local coinfusion of a DA antagonist and agonist. Infusion of 10(-5) M and/or 10(-6) M concentrations of SCH-23390 suppressed a brief increase in DA release induced by both 10(-4) M of APO and 10(-5) M of SKF-38393. On the other hand, 10(-5) M and/or 10(-6) M of sulpiride exerted little or no effect. A possible explanation for this phenomenon was discussed.
Department of Neuropsychiatry, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
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Kurata
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Shibata
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D001923:Brain Chemistry / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid; D003956:Dialysis; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology*; D018492:Dopamine Antagonists; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D013469:Sulpiride / Q000494:pharmacology
D001552:Benzazepines; D015259:Dopamine Agents; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D013469:Sulpiride; D001058:Apomorphine; D004298:Dopamine