![Fig. 6. Effect of intracellular cAMP and cGMP modulation on GPIbα-mediated [Ca++]i elevations in platelets interacting with immobilized VWF. / A blood cell suspension (see the legend for Figure 2) was supplemented with the anti-αIIbβ3 antibody LJ-CP8 (100 μg/mL) and 2 mM EGTA to block [Ca++]ielevations not mediated by GPIbα. Perfusion and analysis were performed as described in the legend for Figure 5. Before perfusion, samples were incubated at 37°C with either theophylline for 15 minutes (A), sildenafil for 20 minutes (B), or dibutyryl cAMP or 8Br-cGMP for 10 minutes (C). Theophylline was used at a high concentration to offset adsorption by erythrocytes.22 The number of platelets with at least one [Ca++]ielevation of type α/β (no γ peaks were observed in these experiments) was measured, and results are shown normalized to the values observed with control blood cell suspensions left untreated. The data represent the mean ± 95% CI from 5 different experiments.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/100/8/10.1182_blood-2002-02-0514/4/h82023252006.jpeg?Expires=1735535783&Signature=Tja2dV1d4Z-xNy8AnOnoFsugMsBYnZAzGZZz06wFLbC89d~o~pVqgdzz6rXvkFqGWKHAg0xYC~12hFb6cvdr9Ao7P2ec2BlgBqmaCOB8vyZ-801gnmYpGOHAaXaIJgnKuZhUrES0812IkNiR74KW5cPPuASeLt~WN1tQ2MN1asxxHkExkY1YyOIGRUCrGrTb~rjRBV0TXV91Wi4eBlc~C82Ebc-U6XxAFgtNvxdvKDQHcx6W3j51Q~xFAzJ66vJKsmTxKXiv6ovw-sReGK-N3ITT8pMAmRBvZM2a9XWrlf4apOcsWKUeby19Iz6x62x3lpQMlWNXiv-Ss8Ryhnlxvw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Effect of intracellular cAMP and cGMP modulation on GPIbα-mediated [Ca++]i elevations in platelets interacting with immobilized VWF.
A blood cell suspension (see the legend for Figure 2) was supplemented with the anti-αIIbβ3 antibody LJ-CP8 (100 μg/mL) and 2 mM EGTA to block [Ca++]ielevations not mediated by GPIbα. Perfusion and analysis were performed as described in the legend for Figure 5. Before perfusion, samples were incubated at 37°C with either theophylline for 15 minutes (A), sildenafil for 20 minutes (B), or dibutyryl cAMP or 8Br-cGMP for 10 minutes (C). Theophylline was used at a high concentration to offset adsorption by erythrocytes.22 The number of platelets with at least one [Ca++]ielevation of type α/β (no γ peaks were observed in these experiments) was measured, and results are shown normalized to the values observed with control blood cell suspensions left untreated. The data represent the mean ± 95% CI from 5 different experiments.
