TABLE 1.
3H-Prazosin Binding to α1-Adrenoceptors in Human, Monkey, and Rat Cerebellum at 37°C and 23°C
|
Bmax (fmol/mg) |
Prazosin KD (nM) |
CUMI-101 Ki (nM) |
Bmax/Ki |
|||||
| Species | 37°C | 23°C | 37°C | 23°C | 37°C | 23°C | 37°C | 23°C |
| Human | 104 ± 34 | 50 ± 22 | 0.27 ± 02 | 0.04 ± 02 | 2.80 ± 50 | 0.64 ± 12 | 3.7 | 7.8 |
| Monkey | 81 ± 28 | NA | 0.34 ± 09 | 0.06 ± 03 | 3.50 ± 67 | 0.40 ± 07 | 2.3 | NA |
| Rat | 172 ± 42 | 74 ± 9 | 0.34 ± 01 | NA | 5.00 ± 06 | 0.80 ± 02 | 3.4 | NA |
Bmax = maximum number of binding sites; KD = dissociation constant; Ki = (half-maximal inhibitory concentration)/(1 + [radioligand]/KD).
Data are mean ± SD. Concentration-dependent displacement by nonradioactive prazosin was analyzed as homologous saturation curve to estimate Bmax and KD. Concentration-dependent displacement by nonradioactive CUMI was analyzed to provide Ki values, which correct for concentration of 3H-prazosin.