No abstract

Postmortem samples from individuals with schizophrenia (n = 13) and control subjects (n = 10) were investigated for binding of [³H]tiagabine to GABA transporter-1 GAT-1. The binding was analyzed in the cingulate cortex and the caudate nucleus. There were no differences in binding affinity between the groups in any of the investigated areas. The maximum number of binding sites (B_max) was elevated in the schizophrenic cingulate cortex compared to controls (1,264 ± 96 vs. 860 ± 123 fmol/mg of protein). The B_max in the caudate nucleus for schizophrenics (426 ± 40 fmol/mg of protein) was the same as for controls (495 ± 69 fmol/mg of protein). The increase in GAT-1 in schizophrenia could be explained by a modulatory upregulation in the cingulate cortex.

According to the present study, presynaptical alterations in the GABA system are correlated with aging in the frontal cortex of the human brain. Further studies involving a broader range of brain regions seem warranted, to confirm the present findings and to enlarge knowledge about the GABA system in aging.