Effects of serotonin transporters on myocardial cell injury during ischemia/reperfusion in rats

Serotonin (5-HT) reuptake in the heart is mediated by the platelet serotonin reuptake transporter (SERT) and the cardiomyocyte plasma membrane monoamine transporter (PMAT). However, the specific roles of these transporters in myocardial cell injury during ischemia/reperfusion remain unclear. Sprague-Dawley rats underwent left coronary artery occlusion followed by reperfusion. Using cardiac microdialysis technique, fluoxetine (SERT inhibitor, 900 μM) or decynium 22 (PMAT inhibitor, 100 μM) was administered locally to the ischemic region. Myoglobin concentrations in the dialysate were measured during ischemia followed by reperfusion. In the fluoxetine-treated group, peak myoglobin concentration (14,889 ± 1364 ng/mL) during 0–15 min of reperfusion was significantly higher compared to both the control group (9800 ± 1627 ng/mL) and the decynium 22-treated group (8172 ± 877 ng/mL) (P < 0.01 for both). Local SERT inhibition exacerbated myocardial cell injury during ischemia/reperfusion. However, co-inhibition of PMAT reduced myocardial cell injury under SERT inhibition to the control level.