In vivo striatal binding of the D1 antagonist SCH 23390 is not modified by changes in dopaminergic transmission

F Thibaut (1) , J. M. Vaugeois (1) , J J Bonnet (1) , J Costentin (1)

1 ESA 6036 - Unité de neuropsychopharmacologie expérimentale

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.

Domaines: Médecine humaine et pathologie

F Thibaut, J. M. Vaugeois, J J Bonnet, J Costentin. In vivo striatal binding of the D1 antagonist SCH 23390 is not modified by changes in dopaminergic transmission. Neuropharmacology, 1996, 35 (3), pp.267-72. ⟨10.1016/0028-3908(95)00187-5⟩. ⟨hal-02187007⟩