In vivo striatal binding of the D1 antagonist SCH 23390 is not modified by changes in dopaminergic transmission.
The in vivo striatal binding of [3H]SCH 23390, an antagonist of the D1 dopamine receptors, was investigated in mice submitted to pretreatment to either decrease (gammabutyrolactone 750 mg/kg, i.p.) or, increase (3,4-dihydroxyphenylalanine (L-DOPA) 200 mg/kg i.p. plus dexamphetamine 4 mg/kg, s.c.) dopaminergic transmission. Such conditions failed to modify [3H]SCH 23390 binding. However, we observed that dopamine (at concentrations > or = 1 microM), reduced the in vitro binding of [3H]SCH 23390 in membrane fractions. These results suggest that modifications in dopamine neurotransmission do not alter the in vivo quantification of D1 receptors with [3H]SCH 23390, for example, in studies that use positron emission tomography.
Thibaut
F
F
Unité de Neuropsychopharmacologie Expérimentale, Saint Etienne du Rouvray, France.
Vaugeois
J M
JM
Bonnet
J J
JJ
Costentin
J
J
D015107:4-Butyrolactone / Q000494:pharmacology*; D000818:Animals; D001552:Benzazepines / Q000378:metabolism*; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004298:Dopamine / Q000031:analogs & derivatives / Q000378:metabolism; D015259:Dopamine Agents / Q000494:pharmacology*; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D051379:Mice; D017447:Receptors, Dopamine D1 / Q000378:metabolism*
D001552:Benzazepines; D015259:Dopamine Agents; D017447:Receptors, Dopamine D1; D007980:Levodopa; C001746:3-methoxytyramine; D015107:4-Butyrolactone; D003913:Dextroamphetamine; D004298:Dopamine