Figure 4. Losartan is selective for GPVI over TPR.

To assess effects on TPR signalling, platelets were activated with 1 µM U46619 and aggregations followed for 5 minutes in the presence of or absence of drug (n = 3, ± SEM). Collagen (solid black line) and CRP-XL (dashed dark grey line) were both used at 1 µg/ml. Losartan (a) has an IC₅₀ of ∼20 µM for U46619-induced aggregation (solid grey line) while cinanserin (b) has no effect on TPR signaling (solid grey bar). Exposure of P-selectin (CD62P) and FITC-fibrinogen binding was measured by flow cytometry. Losartan (100 µM, c) and cinanserin (100 µM, d) both reduce FITC-fibrinogen binding (black bars) and P-selectin exposure (grey bars) compared to SQ-29548 alone. Statistical analysis was conducted by one-way ANOVA with Sidak's multiple comparisons correction. ns P>0.05, * P<0.05, *** P<0.001, n = 3, ± SEM.