Biphasic effect of locally applied apomorphine and 2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine on the release of striatal dopamine investigated by means of brain dialysis.
The effects of 3 kinds of dopamine (DA) agonists, apomorphine (APO), 2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine (SKF-38393) and quinpirole (QPL), on DA release were examined in the caudate-putamen of the freely moving rat by means of microdialysis during local administration of various concentrations of these DA agonists. Infusion of 10(-4) M and 10(-5) M concentrations of APO and 10(-5) M and 10(-6) M of SKF-38393 induced a brief increase in DA release followed by a marked decrease. This phenomenon was sensitive to tetrodotoxin (10(-6) M) infusion. On the other hand, all the tested doses of QPL, 10(-4) M, 10(-5) M, 10(-6) M and 10(-7) M, reduced DA release without showing transient increase.
Kurata
K
K
Department of Neuropsychiatry, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Shibata
R
R
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D003956:Dialysis; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology*; D004873:Ergolines / Q000494:pharmacology; D008297:Male; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains; D013779:Tetrodotoxin / Q000494:pharmacology
D015259:Dopamine Agents; D004873:Ergolines; D019257:Quinpirole; D013779:Tetrodotoxin; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D001058:Apomorphine; D004298:Dopamine