Pharmacological modifications of dopamine transmission do not influence the striatal in vivo binding of [3H]mazindol or [3H]cocaine in mice.
We have considered the in vivo striatal binding of two ligands of the neuronal dopamine uptake complex: [3H]cocaine and [3H]mazindol. The [3H]cocaine tracer dose labelled the dopamine uptake complex in striatum but not the noradrenaline complex in cerebellum. On the contrary, the [3H]mazindol tracer dose induced a marked labelling of the noradrenaline uptake complex in cerebellum; its prevention by desipramine (5 mg/kg) increased simultaneously the cerebral bioavailability and thereby the striatal labelling of the dopamine transporter. In mice submitted to treatments modifying dopaminergic transmission either to decrease it (gammabutyrolactone, 750 mg/kg, i.p.) or to increase it (L-DOPA, 200 mg/kg, i.p., dexamphetamine, 4 mg/kg, s.c., or their combination), only dexamphetamine pretreatment significantly reduced [3H]cocaine and [3H]mazindol binding. Thus it appears that the level of dopamine transmission would not interfere with the in vivo quantification of striatal dopamine uptake sites assessed with either ligands.
Thibaut
F
F
U.R.A. 1969 CNRS, Institut Fédératif de Recherches Multidisciplinaires sur les Peptides, Saint Etienne du Rouvray, France.
Bonnet
J J
JJ
Vaugeois
J M
JM
Costentin
J
J
D015107:4-Butyrolactone / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D002531:Cerebellum / Q000378:metabolism; D003042:Cocaine / Q000378:metabolism* / Q000494:pharmacology; D003913:Dextroamphetamine / Q000494:pharmacology; D004298:Dopamine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D015259:Dopamine Agents / Q000494:pharmacology; D018765:Dopamine Uptake Inhibitors / Q000378:metabolism* / Q000494:pharmacology; D018757:GABA Modulators / Q000494:pharmacology; D007275:Injections, Intravenous; D007980:Levodopa / Q000494:pharmacology; D008454:Mazindol / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D017072:Neostriatum / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D014316:Tritium / Q000378:metabolism
D015259:Dopamine Agents; D018765:Dopamine Uptake Inhibitors; D018757:GABA Modulators; D014316:Tritium; D007980:Levodopa; D008454:Mazindol; D003042:Cocaine; C001746:3-methoxytyramine; D015107:4-Butyrolactone; D003913:Dextroamphetamine; D004298:Dopamine