TABLE 1.
Effect of stimuli, calcium chelators and inhibitors on the S1P release from erythrocytes
Stimuli were added to erythrocytes preincubated with [3H]Sph for 2 min at 37 °C. After incubation for 10 min at 37 °C, erythrocyte suspensions were centrifuged. Calcium chelators and inhibitors were preincubated with erythrocytes for 10 min at 37 °C. Then [3H]Sph was added, and erythrocyte suspensions were incubated for 20 min at 37 °C. Release rate of S1P was calculated as (amount of medium)/(total amount of medium + erythrocytes). The S1P release rate with no addition of compounds is set at 100%. Values are means with the S.D. BAPTA, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, tetrapotassium salt.
| Compound | Concentration | % of release |
|---|---|---|
| μm | ||
| Stimuli | ||
| None | 100.0 | |
| Thrombin | 5 NIH U/ml | 98.2 ± 2.5 |
| TPA | 0.16 | 114.0 ± 3.1 |
| Ca2+ + 2 μm A23187 | 2,000 | 100.5 ± 3.3 |
| Calcium chelators | ||
| EDTA | 100 | 100.3 ± 1.2 |
| EGTA | 100 | 100.5 ± 2.0 |
| BAPTA | 100 | 101.1 ± 1.9 |
| EDTA + 10 μm A23187 | 100 | 92.0 ± 5.3 |
| EGTA + 10 μm A23187 | 100 | 88.3 ± 2.3 |
| BAPTA + 10 μm A23187 | 100 | 89.7 ± 0.7 |
| Inhibitors | ||
| Glyburide | 500 | 69.4 ± 5.2 |
| MK571 | 50 | 97.9 ± 2.6 |
| Cyclosporine A | 10 | 97.4 ± 2.8 |