Figure 5.

[³H]DPCPX saturation binding (90 min, 37°C in 50 mM Tris(HCl) buffer) to human A₁ receptors stably expressed in CHO cell membranes. (a) Membranes were pretreated with 10 U ml⁻¹ ADA during preparation (as indicated in Methods) and the assays were subsequently performed in the presence of 0.1 U ml⁻¹ ADA. (b) Membranes were pretreated with 7 M urea during preparation (as indicated in Methods). Data points represent the mean+s.e.m. obtained from three separate experiments conducted in triplicate. All other details as for Figure 4.