Fig. 8. Tension recordings from the dorsal aorta showing the vasodilatory effect of nicotine (A) and its effect in the presence of the cyclo-oxygenase inhibitor, indomethacin (B). Vessels were preincubated with indomethacin (10^–5 mol l^–1) for approximately 10 min prior to being pre-constricted with endothelin-1 (ET-1; 10^–8 mol l^–1). At the point of maximal vasoconstriction, nicotine (3x10^–4 mol l^–1) was administered. (C) Mean response (% vasodilation) of nicotine on pre-constricted dorsal aorta and intestinal vein in the absence of (filled bars) and in the presence of indomethacin (open bars). Note that there is no significant difference in the nicotine-mediated dilation (dorsal aorta, P=0.63; intestinal vein, P=0.20; N=5).