Figure 7.

[³H]DPCPX (2 nM) versus R-PIA (a) or CHA (b) competition-binding assays (90 min, 37°C in 50 mM Tris(HCl) buffer) performed at human A₁ receptors stably expressed in CHO cell membranes. Membranes had undergone either 10 U ml⁻¹ ADA pretreatment during the preparation plus subsequent addition of 0.1 U ml⁻¹ ADA in the assay in the absence or presence of 100 μM Gpp(NH)p, or membranes have undergone 7 M urea pretreatment during preparation. All other details as for Figure 6.