Sodium independence of the binding of [3H]GBR 12783 and other dopamine uptake inhibitors to the dopamine uptake complex.
When Na+ was the only cation present in the incubation medium used for the determination of the specific binding of [3H]GBR 12783 in rat striatal membranes, the Na+-dependence between 10 and 210 mM Na+ was not observed. In media with low (10 mM) or high (130 mM) Na+ concentration, mazindol and nomifensine competed with [3H]GBR 12783 for its specific binding site with the same affinities. With the exception of amineptine, all the tested catecholamine uptake inhibitors were equally potent to compete with [3H]GBR 12783 when Na+ concentration was decreased from 130 to 10 mM. These data suggest that the media previously used for the binding studies of tritiated inhibitors of dopamine uptake (Tris-ions buffer and Krebs-Ringer medium) contain ions which could exert inhibitory effects on the specific binding at low Na+ concentration.
D000818:Animals; D001665:Binding Sites; D003342:Corpus Striatum / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D008454:Mazindol / Q000494:pharmacology; D009627:Nomifensine / Q000494:pharmacology; D010879:Piperazines / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*
D010879:Piperazines; D009627:Nomifensine; C039737:1-(2-(diphenylmethoxy)ethyl)-4-(3-phenyl-2-propenyl)piperazine; D012964:Sodium; D008454:Mazindol; D004298:Dopamine