Statins decrease serotonin-induced contractions in coronary arteries of swine in vitro.

Recent evidence suggests that statins improve the status of patients with coronary artery disease not only by reducing cholesterol levels, but also by acting at the level of the endothelium-smooth muscle unit. Previous results from our laboratory showed that these drugs interact with the vascular wall by partially inhibiting calcium-dependent, agonist-induced contractions in rat aortas. To evaluate whether this effect is also extended to the coronary vasculature, we assessed the effect of statins on serotonin (5-HT) induced contractions of left and right coronary arteries of swine. Concentration-response curves for the 5-HT-induced contractions (from 0.1 nmol/l to 100 micromol/l) were calculated on rings from both coronaries in the presence and absence of either (5 micromol/l) pravastatin, mevastatin, simvastatin, lovastatin, or atorvastatin. After a 45-min incubation period, all statins significantly reduced the Emax for the 5-HT-induced contractions, ranging from 51.9 +/- 1.9% (simvastatin) to 15.9 +/- 2.0% (pravastatin) in the left coronary artery and from 48.8 +/- 2.0% (simvastatin) to 17.8 +/- 2.5% (pravastatin) in the right coronary artery. The EC50 values for the 5-HT-induced contractions were 0.150 +/- 0.005 micromol/l for the left coronary artery and 0.171 +/- 0.010 micromol/l for the right coronary artery. These values significantly changed after incubation with statins, ranging from 1.240 +/- 0.101 micromol/l (for simvastatin) to 0.081+/- 0.008 micromol/l (for pravastatin) in the left coronary artery and from 1.410 +/- 0.075 micromol/l (for simvastatin) to 0.084 +/- 0.008 micromol/l (for pravastatin) in the right coronary artery. This evidence supports the possibility that, beyond their lipid-lowering properties, statins may provide a beneficial effect in atherosclerotic patients by reducing the tone in the coronary vasculature, facilitating blood flow to the myocardium.