Figure 3: Inhibition or deletion of Cx40 reduces platelet inside-out signalling and granule secretion.

The effect of ⁴⁰Gap27 on 1 μg ml⁻¹ CRP-XL- (a), 10 μM ADP- (b) and 0.1 U ml⁻¹ thrombin- (c) induced fibrinogen binding was measured by flow cytometry using human PRP. Similarly, fibrinogen binding to Cx40^+/+ and Cx40^−/− mouse platelets was measured using whole blood following stimulation with 1 μg ml⁻¹ CRP-XL (d). Fibrinogen binding obtained with vehicle or Cx40^+/+ was taken as 100%. Human PRP was stimulated with 1 μg ml⁻¹ CRP-XL (e), 10 μM ADP (f) and 0.1 U ml⁻¹ thrombin (g) in the presence and absence of ⁴⁰Gap27 (100 μg ml⁻¹) and the level of P-selectin exposed on surface measured by flow cytometry. Similarly, P-Selectin exposure upon stimulation with 1 μg ml⁻¹ CRP-XL using whole blood obtained from Cx40^+/+ and Cx40^−/− was measured (h). P-selectin exposure with vehicle or Cx40^+/+ was taken as 100%. Human washed platelets were stimulated with 0.5 μg ml⁻¹ CRP-XL in the presence and absence of ⁴⁰Gap27 (100 μg ml⁻¹), and the level of ATP secretion was measured using lumino-aggregometry (i,j). Data represent mean±s.d. (n=4; Student’s t-test, *P<0.05, **P<0.01 and ***P<0.001).