Fig. 4.

Effects of prostanoid inhibitors on dose–response curves for tryptamine-induced vasoconstriction of rat isolated perfused mesentery. Dose–response curves in the absence (□) and presence (■) of A. prostaglandin EP₁ receptor antagonist, AH-6809 (10 μM, n = 4), B. prostacyclin synthase/MAO inhibitor, tranylcypromine (10 μM, n = 5), and C. thromboxane TP receptor antagonist, ICI 192,605 (1 μM, n = 4). * Significantly different points from tryptamine alone, P < 0.05, ** P < 0.01. Each response is the mean ± S.E.M. increase in perfusion pressure.