Table 2.
Competition of agonists versus [3H]-NAD-199 binding to membranes of CHO cells expressing the human 5-HT1A receptor
| Ligand | DPAT | 5-OH DPAT | 6-OH DPAT | 7-OH DPAT | 8-OH DPAT | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| enantiomer | R | S | R | S | R | S | R | S | R | S |
| pKh±s.e.m. | 8.22±0.05 | 7.74±0.19 | 6.53±0.23 | 7.48±0.18 | 6.32±0.09 | 7.04±0.36 | 7.45±0.13 | 6.84±0.20 | 9.26±0.12 | 9.76±0.33 |
| (Kl(nM)) | (6.0) | (18) | (280) | (33) | (480) | (92) | (35) | (145) | (0.55) | (0.18) |
| pKl±s.e.m | 6.09±0.01 | 5.96±0.03 | 5.07±0.13 | 5.54±0.13 | 4.61±0.12 | 5.22±0.06 | 5.57±0.04 | 5.42±0.09 | 7.24±0.05 | 7.81±0.10 |
| (Kl(nM)) | (813) | (1109) | (8433) | (2884) | (24320) | (5984) | (2685) | (3784) | (58) | (15) |
| Rh±s.e.m % | 51.0±4.0 | 49.1±4.5 | 51.4±12.1 | 38.6±7.9 | 40.6±3.5 | 21.6±5.2 | 53.3±0.8 | 47.5±5.8 | 44.7±7.4 | 38.4±4.6 |
| n | 3 | 3 | 3 | 4 | 8 | 3 | 4 | 4 | 6 | 4 |
The binding of a series of agonists was determined in competition versus [3H]-NAD-199 as described in the Methods section. Competition curves were fitted well by two-binding site models in all cases (P<0.05), and Kh, Kl and percentage higher affinity site (Rh) values (mean± s.e.m., n experiments) are recorded.