抄録
Since the pathophysiology of schizophrenia have been discussed with a functional alteration of dopaminergic transmission in the brain, we have focused the dopaminergic components for the research target of schizophrenia using PET. Using high affinity ligand [11C]FLB 457, we found reduced D2 receptor binding in the anterior cingulate cortex of patients with schizophrenia, and a significant negative correlation was observed between D2 receptor binding and the positive symptom score. Subregions of interest were defined on the thalamus using individual magnetic resonance images. D2 receptor binding was also lower in the central medial and posterior subregions of the thalamus in patients with schizophrenia. Based on the recent findings, cortical D2 receptor may interact with GABA system working to modulate DA release, while thalamic D2 receptor is likely to participate in sensory gating function over the prefrontal cortex. We have found decreased D2 receptor in the anterior cingulate cortex and thalamic subregions of the patient with schizophrenia. These observations could lead to the view that alterations of extrastriatal D2 receptor is involved in dysregulation of DA release and sensory signals from the thalamus to the cortex. On the other hand D1 receptor binding was found to be lower in the prefrontal cortex and a significant negative correlation was observed between D1 receptor binding and the negative symptom score. Abnormality of D1 receptor function would be at the bottom of the negative symptoms and cognitive impairment of schizophrenia. [J Physiol Sci. 2008;58 Suppl:S16]
