Fig. 5.

Effects of amiloride (A) and amiloride analogues (B) on the dissociation of [¹²⁵I]I-AB-MECA from human A₃ adenosine receptors expressed in CHO cells. [¹²⁵I]I-AB-MECA (1.0 nM) was pre-associated with the A₃ adenosine receptor membranes for 1 hr at 25° in a total assay volume of 200 μL. Nonspecific binding was determined in parallel by the addition of 3 μM Cl-IB-MECA before the pre-association. After 1 hr pre-association, dissociation was initiated by the addition of Cl-IB-MECA (final concentration, 3 μM) alone or with the amiloride analogues. The data shown were derived from one experiment performed in duplicate and are typical of three independent experiments giving similar results. The k₋₁ values were calculated from three independent experiments and are listed in Table 1.