Dysregulated glutamate and dopamine transporters in postmortem frontal cortex from bipolar and schizophrenic patients

Background ulated glutamate, serotonin and dopamine neurotransmission has been reported in bipolar disorder (BD) and schizophrenia (SZ), but the underlying mechanisms of dysregulation are not clear. We hypothesized that they involve alterations in excitatory amino acid transporters (EAATs), the serotonin reuptake transporter (SERT), and the dopamine reuptake transporter (DAT). s t this hypothesis, we determined protein and mRNA levels of EAAT subtypes 1–4, of the SERT and of the DAT in postmortem frontal cortex from BD (n = 10) and SZ (n = 10) patients and from healthy control (n = 10) subjects. s ed to control levels, protein and mRNA levels of EAAT1 were increased significantly in cortex from both BD and SZ patients. EAAT2 protein and mRNA levels were decreased significantly in BD but not in SZ cortices. EAAT3 and EAAT 4 protein and mRNA levels were significantly higher in SZ but not in BD compared with control. DAT protein and mRNA levels were decreased significantly in both BD and SZ cortices. There was no significant change in SERT expression in either BD or SZ. sions tered EAATs and DAT expression could result in altered glutamatergic and hyperdopaminergic function in BD and SZ. Differently altered EAATs involved in glutamatergic transmission could be therapeutic targets for treating BD and SZ.