Fig. 5. Co-immunoelution of sG_i2 protein with D_2S and D_2L receptor from the extract of monkey brain. Similar to Fig. 4, extract from the substantia nigra was passed through immunoaffinity columns as indicated. Eluted proteins were then identified in immunoblots with antibodies raised against D_2S (lanes 1, 4), sG_i2 (lanes 2, 3), D_2L (lane 5), D₁ (lane 6). sGi2 antibody co-eluted D_2S and D_2L receptors but not D₁ receptor.