Target Size of Dopamine D-1 Receptors in Rat Corpus Striatum Estimated by Binding of the Benzazepine 3H-SCH 23390

: The binding characteristics of 3H-SCH 23390 in rat striatum prepared in potassium phosphate buffer are described. The amount of binding sites labeled by 3H-SCH 23390 decreased monoexponentially when exposed to increasing radiation dose. The molecular weight was determined to 78,000 daltons similar to the molecular mass of 3H-piflutixol binding to D-1 receptor previously reported, however lower than the molecular mass of dopamine D-1 agonist binding sites (Gredal & Nielsen 1987).