TABLE 2.
Computer-assisted estimates of Kd values of α2AAR affinity states and percentage of α2AAR in the guanine-nucleotide sensitive higher affinity state
UK14,304 competition for [3H]rauwolscine binding was determined in well-washed particulate fractions, to eliminate endogenous guanine nucleotides, in the absence or presence of Gpp(NH)p, as outlined under Materials and Methods. Binding profiles in the absence of Gpp(NH)p were best fit by a two-site model, whereas those obtained in the presence of Gpp(NH)p fit a one-site model. The interaction of the two-state analysis, in terms of receptor interactions with G proteins, is provided in the text.
| Genotype | −Gpp(NH)p |
RH% | +Gpp(NH)p (−logKd) | |
|---|---|---|---|---|
| −logKH | −logKL | |||
| WT | 8.2 ± 0.3 | 6.6 ± 0.2 | 42 ± 8 | 6.5 ± 0.1 |
| Sp(−/−) | 8.1 ± 0.2 | 6.4 ± 0.3 | 72 ± 7* | 6.4 ± 0.1 |
RH% indicates the percentage of receptors at a higher affinity state of agonist.
*
P < 0.05.