Fig. 6. Tension recordings showing the effect of acetylcholine (ACh) on the lateral aorta with (A) or without (B) the nNOS inhibitor vinyl-L-NIO. The preparations were exposed to endothelin-1 (ET-1; 10^-8 moll^-1) until a maximum constriction was achieved and then vinyl-L-NIO (10^-4 moll^-1) was added for approximately 10min. Subsequently, ACh (10^-5 moll^-1) was added. The vasodilatory response was reduced in the presence of vinyl-L-NIO. (C) Mean response (% vasodilation) of ACh on ET-1-constricted lateral and dorsal aortae with (filled bars) or without (open bars) the presence of vinyl-L-NIO. Note that vinyl-L-NIO significantly reduced the ACh-mediated vasodilation (lateral and dorsal aortae, P<0.05, ^*denotes significant difference; N=5).