Low GSK-3β immunoreactivity in postmortem frontal cortex of schizophrenic patients

Objective: Glycogen synthase kinase-3 (GSK-3) is a protein kinase that is highly abundant in the brain. It is involved in signal transduction cascades of multiple cellular processes, particularly neurodevelopment. In an attempt to explore possible involvement of GSK-3 beta in psychiatric disorders, the authors examined its levels in postmortem brain tissue. Method: Western blot analysis was performed to measure GSK-3 beta in the frontal cortex of 14 schizophrenic patients, 15 patients with bipolar disorder, 15 patients with unipolar depression, and 14 normal comparison subjects. Results: GSK-3 beta levels were 41% tower in the schizophrenic patients than in the comparison subjects. Other diagnostic groups did not differ from the com parison subjects. Conclusions: These resuits a re consistent with the notion that schizophrenia involves neurodevelopmental pathology. It remains to be investigated whether the active fraction of GSK-3 beta, or its activity is also low in frontal cortex of schizophrenic patients and if this is also reflected in other brain regions.