Effects of serotonin on platelets and blood vessels.

We advance the hypothesis that ketanserin, a 5-HT2 receptor antagonist, may provide vascular protection. This is due mainly to inhibition of the effect of serotonin, released by platelets activated at the site of arterial wall injury, on platelets and vascular smooth muscle cells which contribute to vascular smooth muscle cell proliferation and connective tissue synthesis, vasospasms in areas of defective endothelial cell-dependent relaxation and to platelet-dependent thrombus formation in various experimental scenarios. Clinical data obtained so far with ketanserin in patients, subjected to coronary angioplasty, with critical coronary stenosis and at risk for vascular accidents due to atherosclerosis, suggest that, within certain limitations, vascular protection by ketanserin might also occur in man.