Selected variables characteristic of platelet interaction with immobilized VWF and Ca++ signaling under different conditions
| Condition . | Translocation velocity (μm/s) . | Mean arrest time in seconds (range) . | Stable adhesion, % . | Aggregation . | Results according to type of [Ca++]i peak . | ||||
|---|---|---|---|---|---|---|---|---|---|
| Frequency, % . | Concentration, nM . | ||||||||
| α/β . | γ . | α . | β . | γ . | |||||
| Control | 1.9 ± 0.4 | 5.51 ± 2.6 (0.2-30) | 9.2 ± 2.6 | + | 20.3 ± 6.2 | 3.5 ± 1.2 | 1503 ± 299 | 301 ± 33 | 2328 ± 601 |
| Apyrase | 2.4 ± 0.4 | 5.70 ± 2.5 (0.3-30) | 8.5 ± 3.1 | − | 22.4 ± 4.5 | 0 | 1339 ± 321 | 297 ± 30 | 0 |
| Wortmannin | |||||||||
| 10 nM | 2.2 ± 0.3 | 5.50 ± 2.2 (0.2-30) | 8.9 ± 2.2 | − | 21.3 ± 3.6 | 0 | 1412 ± 276 | 312 ± 42 | 0 |
| 100 nM | 2.9 ± 0.2* | 5.21 ± 2.1 (0.2-30) | 7.5 ± 2.8 | − | 19.8 ± 4.2 | 0 | 1289 ± 342 | 287 ± 32 | 0 |
| Anti-αIIbβ3 | 4.6 ± 0.5† | 1.19 ± 0.56 (0.2-3.78)† | 0 | − | 23.7 ± 3.2 | 0 | 1278 ± 277 | 293 ± 45 | 0 |
| BAPTA-AM | 5.2 ± 0.3† | 1.08 ± 0.49 (0.2-3.08)† | 0 | − | 0 | 0 | 0 | 0 | 0 |
| Sodium nitroprusside | 5.6 ± 0.3† | 0.98 ± 0.44 (0.2-2.48)† | 0 | − | 0 | 0 | 0 | 0 | 0 |
| Condition . | Translocation velocity (μm/s) . | Mean arrest time in seconds (range) . | Stable adhesion, % . | Aggregation . | Results according to type of [Ca++]i peak . | ||||
|---|---|---|---|---|---|---|---|---|---|
| Frequency, % . | Concentration, nM . | ||||||||
| α/β . | γ . | α . | β . | γ . | |||||
| Control | 1.9 ± 0.4 | 5.51 ± 2.6 (0.2-30) | 9.2 ± 2.6 | + | 20.3 ± 6.2 | 3.5 ± 1.2 | 1503 ± 299 | 301 ± 33 | 2328 ± 601 |
| Apyrase | 2.4 ± 0.4 | 5.70 ± 2.5 (0.3-30) | 8.5 ± 3.1 | − | 22.4 ± 4.5 | 0 | 1339 ± 321 | 297 ± 30 | 0 |
| Wortmannin | |||||||||
| 10 nM | 2.2 ± 0.3 | 5.50 ± 2.2 (0.2-30) | 8.9 ± 2.2 | − | 21.3 ± 3.6 | 0 | 1412 ± 276 | 312 ± 42 | 0 |
| 100 nM | 2.9 ± 0.2* | 5.21 ± 2.1 (0.2-30) | 7.5 ± 2.8 | − | 19.8 ± 4.2 | 0 | 1289 ± 342 | 287 ± 32 | 0 |
| Anti-αIIbβ3 | 4.6 ± 0.5† | 1.19 ± 0.56 (0.2-3.78)† | 0 | − | 23.7 ± 3.2 | 0 | 1278 ± 277 | 293 ± 45 | 0 |
| BAPTA-AM | 5.2 ± 0.3† | 1.08 ± 0.49 (0.2-3.08)† | 0 | − | 0 | 0 | 0 | 0 | 0 |
| Sodium nitroprusside | 5.6 ± 0.3† | 0.98 ± 0.44 (0.2-2.48)† | 0 | − | 0 | 0 | 0 | 0 | 0 |
Results were obtained by using the perfusion conditions described in the legend for Figure 2, with a wall-shear rate of 3000 seconds−1. The values shown are the mean ± 95% CI, except for aggregation, which was assessed qualitatively. Between 200 and 250 platelets were examined in 5 separate experiments for all conditions except BAPTA-AM, in which case 135 platelets were examined in 3 separate experiments. Stable adhesion represents the number of platelets that arrested in the same position for at least 30 seconds relative to the total number of platelets analyzed in the field of view. The frequency of the different types of [Ca++]i peaks is expressed as the percentage of platelets showing at least one Ca++ oscillation of a given type relative to the total number analyzed in the field of view during a 30-second observation period. Apyrase was used at a final concentration of 10 U/mL; the anti-αIIbβ3antibody LJ-CP8 at 100 μg/mL; BAPTA-AM at 80 μM; and sodium nitroprusside at 5 μM.
P < .05 compared with control.
P < .01 compared with control.