Comparison of the potencies of different tachykinins
| Peptide | Ki | Ratio of [3H][Pro9]SP to [3H]ALIE-124 | EC50 | ||
|---|---|---|---|---|---|
| [3H][Pro9]SP | [3H]ALIE-124 | Inositol phosphates | cAMP | ||
| nm | nm | ||||
| SP | 1.6 ± 0.43-a | 0.22 ± 0.02 | 7 | 1.0 ± 0.63-a | 8 ± 23-a |
| NK-A | 4700 ± 2003-a | 4.9 ± 1.1 | 960 | 6 ± 2 | 1240 ± 603-a |
| NK-B | >50003-a | 27 ± 5 | 300 ± 50 | >50003-a | |
| [Pro9]SP | 1.1 ± 0.13-a | 0.15 ± 0.04 | 7 | 0.8 ± 0.2 | 10 ± 2 |
| 1.20 ± 0.043-b | 0.56 ± 0.073-b | 2 | |||
| Septide | 490 ± 103-a | 2.4 ± 0.5 | 204 | 2.7 ± 0.53-a | 5200 ± 2003-a |
| ALIE-124 | 4200 ± 300 | 8.0 ± 0.7 | 525 | 37 ± 4 | >5000 |
| 250 ± 503-b | 17 ± 43-b | 15 | |||
| [Lys5,methyl-Leu9,Nle10]NKA(4–10) | 5000 ± 10003-a | 68 ± 10 | 73 | 170 ± 30 | >50003-a |
| Senktide | >50003-a | >5000 | >50003-a | >50003-a | |
| RP 67580 | 92 ± 113-a | 15 ± 1 | 6 | ||
Comparison was made of the ability to compete with [3H]ALIE-124 or [3H][Pro9]SP and to stimulate both inositol phosphates and cAMP second messenger pathways in intact CHO cells expressing human NK-1 receptors, as described in the text.