Effect of Y403F mutation on phosphatidylinositol stimulation in whole-cell assays
| Agonist | n | EC50 | Stimulation2-a | [R] | Wild-type EC50 | Wild-type stimulation |
|---|---|---|---|---|---|---|
| μm | fold | pmol · dm−2 | μm | fold | ||
| Acetylcholine | 2 | 60 ± 4 | 1.6–2.6 | 1.3–5.0 | 0.4 ± 0.2 | 1.2–1.4 |
| Carbachol | 4 | 140 ± 70 | 2.4–3.0 | 5.0–33 | 1.2 ± 0.5 | 1.6–2.4 |
| Oxotremorine M | 2 | 40 ± 3 | 1.6–2.6 | 1.3–5.0 | 1.0 ± 0.5 | 1.4–1.5 |
| Pilocarpine | 6 | N.S. | N.S. | 0.7–10.8 | 10 ± 4 | 1.1–1.3 |
Values for EC50 and fold maximal stimulation of phosphatidylinositol metabolism are shown for the indicated receptor site densities. These values are compared with the wild-type values for the same range of receptor site densities observed in wild-type-expressing CHO cells from data previously reported (20). Results with pilocarpine were not significant. EC50 values are presented ± standard deviation.
↵2-a Maximal stimulation increased with increasing [R] as in wild-type.