Table 1.
Affinities of tracers and expression levels of Gq family (Gαq/11/14) proteins determined by saturation binding expressed as pKD ± SD
| [3H]PSB‐15900 | ||
|---|---|---|
| Tissue and temperature | pKD ± SD (nM) | Bmax ± SD (pmol·mg−1 of protein) |
| Human platelet membranes 0°Ca , b | 8.04 ± 0.09 | 5.44 ± 0.42 |
| Human platelet membranes 21°Ca , b , c | 8.09 ± 0.12 | 3.86 ± 0.12 |
| Human platelet membranes 37°Ca , b , d | 8.45 ± 0.31 | 4.02 ± 0.65 |
| [3H]PSB‐16254: | [3H]PSB‐16254: | |
| 7.96 ± 0.10 | 7.09 ± 3.89 | |
| Intact human platelets 37°Ca , e | 8.00 ± 0.15 | 10600 ± 2100 binding sites/cell |
| Rat brain cortical membranes 0°Ca , b | 8.26 ± 0.19 | 19.7 ± 9.6 |
a
Values represent data from five independent experiments performed in duplicates; apparent pKD values are reported.
b
For curves, see Figure 2.
c
For curves, see Figure S3.
d
Comparison of KD values determined for [3H]PSB‐15900 and [3H]PSB‐16254 revealed a statistical significance (unpaired two‐tailed t‐test). The affinity of [3H]PSB‐15900 is likely underestimated due to its extremely low dissociation kinetics.
e
For curves, see Figure S4.