Figure 5.

Putative pathway involving in the 5‐HT metabolism during ischemia and reperfusion in the heart. In a baseline condition (left), PMAT takes up 5‐HT into cells including cardiomyocytes, endothelial cells, and fibroblast cells to maintain background level of interstitial 5‐HT lower. During ischemia (middle), PMAT keeps the 5‐HT uptake rate while interstitial 5‐HT increases. In spite of the increase in intracellular 5‐HT, interstitial 5‐HIAA does not change due to reduced 5‐HT degradation in the cells. During reperfusion (right), high‐capacity transporter PMAT contributes to the clearance of the increased interstitial 5‐HT, meanwhile reoxygenation may accelerate 5‐HT degradation, therefore, intracellular 5‐HT is metabolized to 5‐HIAA