[Binding of a tetrabenazine derivative to the monoamine transporter of the chromaffin granule membrane].

[2-3H] dihydrotetrabenazine (2-hydroxy-3-isobutyl-9-10-dimethoxy-1,2,3,4,6,7 hexahydro-11 bH-benzo [a] quinolizine), a derivative of tetrabenazine obtained by tritiated borohydride reduction, binds to the membrane of purified chromaffin granules. The binding equilibrium has been studied by filtration and by centrifugation of ligand-membrane complexes. Saturable binding sites (190 pmol/mg protein), characterized by a dissociation equilibrium constant KD = 90 nM have been described. The correlation existing between dihydrotetrabenazine site occupancy and noradrenaline uptake inhibition indicates that these sites are located on the monoamine transporter.