To study smooth muscle function in atherosclerosis, we calculated dose-resp
onse curves in patients with coronary artery disease and in controls by mea
suring changes in brachial artery diameter after incremental sublingual dos
es of nitroglycerin. The doses required to produce a 50% maximal dilator re
sponse were significantly higher in patients with coronary artery disease t
han in controls (p < 0.002), suggesting smooth muscle dysfunction in athero
sclerosis.