Fig. 8.

Effect of platelets and the P2Y₁₄ receptor antagonist PPTN, on porcine coronary artery contractility. Platelets isolated from 7 healthy adult human donors were added to U46619-preconstricted porcine coronary arteries in the absence (a–c) and presence (d–g) of L-NAME (100 μM), a nitric oxide synthase inhibitor, in the absence and presence of PPTN (1 μM) (P2Y₁₄ receptor antagonist). In the absence of L-NAME the platelets elicited vasorelaxation. In the presence of L-NAME platelets elicited vasoconstriction. n indicates the number of different pigs from which coronary artery segments were obtained. *P < 0.05; **P < 0.01 for comparison of responses in the absence and presence of PPTN (two way ANOVA). Data are mean ± S.E.M.