Fig. 4. (A) Tension recording showing the vasodilatory effect of nicotine on the dorsal aorta. The vessels were preconstricted with endothelin-1 (ET-1; 10^–8 mol l^–1) and at the point of maximum constriction, nicotine (3x10^–4 mol l^–1) was added, which caused a marked dilation. Similar results were observed in the intestinal vein. (B) Mean responses (% vasodilation) of preconstricted dorsal aorta and intestinal vein to nicotine (3x10^–4 mol l^–1; N=5).