Table 2.
Inhibition of specific binding of 3H-DPCPX to the adenosine A1-receptor by fluorescent analogues of NECA and XAC
| Log KD1 | Log IC50 | % Inhibition2 | n | |
|---|---|---|---|---|
| NECA | −5.97 ± 0.03 | 8 | ||
| APrEA-X-BY630 | −6.62 ± 0.09 (apparent) | −6.51 ± 0.10 | 55.4 ± 2.5% | 10 |
| ABEA-X-BY630 | −5.93 ± 0.10 (apparent) | −5.81 ± 0.10 | 46.2 ± 4.9% | 10 |
| APEA-X-BY630 | −6.01 ± 0.25 (apparent) | −5.89 ± 0.25 | 45.3 ± 4.2% | 9 |
| AOEA-X-BY630 | −6.15 ± 0.21 (apparent) | −6.04 ± 0.21 | 19.7 ± 3.6% | 7 |
| ADOEA-X-BY630 | −6.19 ± 0.24 (apparent) | −6.23 ± 0.23 | 24.3 ± 4.8% | 7 |
| ABEA-dansyl | >−4 | 5 | ||
| ABEA-AO-dansyl | NI | 3 | ||
| AUEA-dansyl | −4.97 ± 0.15 (apparent) | −4.83 ± 0.15 | 44.8 ± 2.3% | 6 |
| ABEA-X-Texas Red | >−4 | 6 | ||
| ABEA-EVOBlue 30 | >−5 | 2 | ||
| ABEA-Cy5 | NI | 4 | ||
| ABEA-BYFL | NI | 4 | ||
| ABEA-X-BYFL | >−4 | 5 | ||
| XAC | −7.38 ± 0.05 | 11 | ||
| XAC-X-BY630 | −7.42 ± 0.05 (apparent) | −7.28 ± 0.05 | 82.3 ± 1.4% | 10 |
| XAC-X-Texas Red | −5.72 ± 0.07 | 7 | ||
| XAC-AEAO-BYFL | NI | 5 | ||
| XAC-EVOBlue 30 | −5.27 ± 0.11 | 6 | ||
| XAC-Cy5 | −5.59 ± 0.02 | 6 | ||
| XAC-dansyl | −6.71 ± 0.05 | 7 | ||
| XAC-AO-dansyl | −6.91 ± 0.09 (apparent) | −6.77 ± 0.09 | 91.0 ± 0.5% | 6 |
| XAC-AHH-dansyl | −6.87 ± 0.05 (apparent) | −6.73 ± 0.04 | 81.0 ± 0.9% | 6 |
All values are mean ± SEM.
Unless otherwise stated, KD values were calculated as described under Methods. In those situations where a maximal inhibition of specific binding was obtained that was less than 100% (defined with 10 µM XAC), an apparent KD was calculated from the IC50 of the displaceable component of binding.
Where indicated, maximum inhibition of specific binding was obtained that was less than that defined with 10 µM XAC.
ABEA, N6-(4-aminobutyl)-5′-ethylamino-5′-oxo-5′-deoxyadenosine; ADOEA, N6-(8-amino-3,6-dioxaoctyl)-5′-ethylamino-5′-oxo-5′-deoxyadenosine; AEAO, 8-(2-aminoethylamino)-8-oxooctanoyl; AHH, 6-(6-aminohexanamido)hexanoyl (See Figures 1 and 2 for complete structures); 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; AUEA, N6-(11-aminoundecyl)-5′-ethylamino-5′-oxo-5′-deoxyadenosine; NECA, 5′(N-ethylcarboxamido)adenosine; NI, no inhibition of specific binding at concentrations up to 0.1 mM; X, 6-aminohexanoyl; XAC, xanthine amine congener.