Characterization of cAMP PDE Activities in HASMCs
| Addition | cAMP PDE Activity | Inhibition |
|---|---|---|
| pmol/min/mg protein | % | |
| Vehicle | 159 ± 4 | |
| PDE1, calmodulin (4 μg/ml) and calcium (800 μM) | 1934 ± 94 | |
| PDE3, cilostamide (1 μM) | 121 ± 1 | 24 |
| PDE4, Ro 20-1724 (10 μM) | 164 ± 5 | |
| Cilostamide + Ro 20-1724 | 117 ± 2 | 26 |
| 3-Isobutyl-1-methylxanthine (500 μM) nonselective | 16 ± 1 | 90 |
Activities are means ± S.E. of a representative experiment carried out in triplicate using 1 μM cAMP as substrate. Similar values were obtained in six separate experiments. All values are significantly different (P < .05; one-way ANOVA with Tukey post hoc test) relative to control with the exception of the determination of the activity in the presence of Ro 20-1724.