Serotonin transporter It is believed that about 80% occupancy of the serotonin transporter is needed for a serotonergic antidepressant to be efficacious (Meyer, 2007). Negative feedback of serotonin release Serotonin release in the brain is controlled in part by multiple negative feedback loops. When a serotonin reuptake inhibitor is started and serotonin release increases, these negative…