Serotonin uptake

The serotonin transporter protein (SERT) is a monoamine transporter protein that is responsible for terminating serotonin binding and then recycling the compound. Transport of serotonin into the cell is driven by higher concentration of Na+ outside the cell, which is maintained by Na+/K+ pumps. One mechanism that antidepressant medications use is to reduce SERT activity so that there is more serotonin available to bind with serotonin receptors. One of the most common classes of antidepressants selective serotonin reuptake inhibitors (SSRIs) act by binding to SERT and reducing SERT’s affinity for serotonin (thus preventing its transported back into the neuron).