Fig. 6.

Saturation studies (A) and Scatchard plot analysis (B) of in vivo binding of [¹¹C]raclopride in the monkey brain. Monkeys were administered saline or scopolamine (10 or 100 μg/kg, i.v.) 30 min before injection of [¹¹C]raclopride under carrier-free conditions or with various doses of carrier ligand ranging from 3 to 300 μg/kg. A, The radioactivities in striatum and cerebellum at 12–15 min after tracer injection were expressed as percentage of dose per milliliter. Data are expressed as means ± SD for four animals per treatment group. Radioactivity in the striatum (open symbols) or cerebellum (filled symbols). B, The total radioligand concentration in the cerebellum was used as the free radioligand concentration (Free) in the striatum. Specific binding (Bound) was defined as radioactivity in the striatum reduced with Free. The average values (n = 4 for each points) for Boundand Free were used in a Scatchard analysis in which the ratios Bound/Free were plotted againstBound.