Subsequently, Han et al. found that the presynaptic membrane transporter dopamine transporter (DAT) of dopaminergic neurons can reuptake the DA from the synaptic terminals to maintain the physiological concentration of DA in the synaptic gap and found that the density of DAT in the striatum of patients with depression is significantly higher than that of normal controls [77]. The gene discussed is SLC6A3; the disease is depressive symptom measurement.