Figure 1

Calcium release from intracellular stores in either untreated or citalopram-treated platelets. Example traces are shown for both (a) cross-linked collagen-related peptide (CRPXL)-stimulated (0.5 µg mL⁻¹) and (c) U46619-stimulated (0.2 µM) platelets, either untreated or pre-treated with citalopram (100 µM) for approximately 5 min. (b,d) After the addition of agonist, the cytosolic concentration of Ca²⁺ ([Ca²⁺]_cyt) in platelets pre-incubated with citalopram (0, 10, 20, 50, 100 & 200 µM) was recorded for 3 min. The maximum increase in [Ca²⁺]_cyt following agonist addition (Max. Δ[Ca²⁺]_cyt) was used to generate concentration-response curves, using the four-parameter logistic (4PL) model (N = 7 blood donors). (e) In a separate experiment, using platelets from the same blood donor on the same experimental day, [Ca²⁺]_cyt (solid lines) and aggregation (dashed line) were separately recorded following pre-incubation with or without citalopram (200 µM) and stimulation with U46619 (0.2 µM) (N = 1 blood donor).