FIGURE 2.

Radioligand binding to striatal membranes. Pooled membranes from striata of 12 wild-type littermates (A) or 12 Gng7^−/− mice (B), showing ¹²⁵I-APE specifically bound at various concentrations in the absence (filled boxes) or presence (open boxes) of GTPγS. The difference ± GTPγS is defined as GTPγ-S sensitive binding. Note reduced GTPγS-sensitive binding to Gng7^−/− membranes compared with controls. The total number of receptors was determined from binding of the antagonist, ¹²⁵I-ZM241385 (C). The ratio of specific binding of ¹²⁵I-APE ± GTPγS/¹²⁵I-ZM241385 was measured in 12 individual membrane preparations from wild type or Gng7^−/− mice, as an index of receptor coupling to G proteins (D).