Serotonin blockade protects against early microvascular constriction following atherosclerotic plaque rupture

Early microvascular constriction following atherosclerotic plaque rupture may be mediated via serotonin and/or endothelin-1. Atherosclerotic lesions in the rabbit hindlimb underwent plaque rupture, resulting in a rapid reduction of distal flow (7.1 +/- 0.7 ml/min pre-rupture versus 3.6 +/- 0.6 ml/min post-rupture, P < 0.001) and a rise in distal microvascular resistance (10.5 +/- 0.9 mm Hg min/ml pre-rupture versus 23.5 +/- 3.5 mm Hg min/ml post-rupture, P = 0.01). Distal microvascular resistance remained elevated following endothelin-1 receptor antagonism and control vehicle, but normalised after serotonin receptor antagonism with ritanserin (10.5 +/- 0.9 mm Hg min/ml pre-rupture versus 22.2 +/- 6.0 mm Hg min/ml post-endothelin-1 receptor antagonism [P < 0.05] versus 21.6 +/- 6.2 mm Hg min/ml post-control vehicle [P < 0.05] versus 11.6 +/- 2.0 turn Hg min/ml post-ritanserin [P = NS]). Early antagonism of serotonin receptors protects against distal microvascular constriction following atherosclerotic plaque rupture. (C) 2004 Elsevier B.V. All rights reserved.