FIGURE 3. [³H]Ro15-4513 binding to control (+/+) and stargazer (stg) cerebellar membrane homogenates.

Full saturation [³H]Ro15-4513 binding curves were generated using +/+ and stg cerebellar membranes and a concentration range of 0.3–40 nm [³H]Ro15-4513. Nonspecific binding was determined in the presence of Ro15-1788 (10 μm). [³H]Ro15-4513 binding in the presence of flunitrazepam (10 μm), defined BZ-IS-binding sites, and hence benzodiazepine-sensitive (BZ-S) sites could be determined by subtraction of the BZ-IS-binding sites from total [³H]Ro15-4513 specific binding sites. The bar graph illustrates the difference in B_max values calculated for [³H]Ro15-4513 binding to +/+ and stg membranes. Results show differences in B_max for total specific binding (100 ± 5% and 81 ± 7%), BZ-S binding (100 ± 11% and 92 ± 9%), and BZ-IS binding (100 ± 3% and 57 ± 12%) in +/+ and stg membranes, respectively. The table summarizes the estimated B_max and K_D values for [³H]Ro15-4513 binding to +/+ and stg cerebellar membranes. Data are representative of the mean ± S.E. for assays conducted in triplicate on two separate membrane preparations per mouse strain (n = 6). Ten cerebella were used for each preparation per mouse strain.