Figure 3.

Inhibition of the specific binding of ³H-DPCPX by fluorescent (A) antagonists and (B) agonists in CHO-A1 cells expressing the human adenosine A₁ receptor. Non-specific binding was defined with 10 µM XAC. ³H-DPCPX was used at (A) 1.30 nM or (B) 1.11 nM. Values represent mean ± SEM from triplicate determinations in a single experiment. These separate experiments are representative of (A) five and (B) seven separate experiments. AEAO, 8-(2-aminoethylamino)-8-oxooctanoyl; AO, 8-aminooctanoyl; AOEA, N⁶-(8-aminooctyl)-5′-ethylamino-5′-oxo-5′-deoxyadenosine; APEA, N⁶-(5-aminopentyl)-5′-ethylamino-5′-oxo-5′-deoxyadenosine; APrEA, N⁶-(3-aminopropyl)-5′-ethylamino-5′-oxo-5′-deoxyadenosine; X, 6-aminohexanoyl; CHO, Chinese hamster ovary; DPCPX, 8-cyclopentyl-1,3-dipropylxanthine; NECA, 5′ (N-ethylcarboxamido)adenosine; X, 6-aminohexanoyl; XAC, xanthine amine congener.