Preferential adsorption of dopamine antagonist binding sites by fluphenazine-agarose.
Separation of dopamine (DA) agonist and antagonist receptors was attempted by means of a covalently-bound fluphenazine-agarose (Flu-agarose). Incubation of striatal membranes with Flu-agarose resulted in loss of 3H-spiroperidol (3H-SPI) binding sites, while incubation with non-coupled agarose did not cause any change. The loss of 3H-SPI binding to the Flu-agarose treated membranes was not attributed to the release of fluphenazine from Flu-agarose as justified by several criteria. Flu-agarose adsorbed more effectively striatal membranes with 3H-SPI binding sites than those with 3H-DA binding sites. Following incubation of the membranes with Flu-agarose (2.5 ml beads/100 mg membrane protein), the density of 3H-SPI binding sites in the resulting membranes was reduced to 29%, whereas the density of 3H-DA binding sites to the same membranes was not changed. In addition, the potencies of DA antagonists to inhibit 3H-N-propylnorapomorphine binding to the membranes were decreased more than a hundred times, while the potencies of DA agonists were little affected. These results suggest that in the striatal membranes exist at least two populations of DA receptors.
D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002846:Chromatography, Affinity / Q000379:methods; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism; D018492:Dopamine Antagonists; D005476:Fluphenazine; D007700:Kinetics; D011954:Receptors, Dopamine / Q000302:isolation & purification* / Q000378:metabolism; D013134:Spiperone / Q000378:metabolism
D018492:Dopamine Antagonists; D011954:Receptors, Dopamine; D013134:Spiperone; D005476:Fluphenazine; D004298:Dopamine