2019 Volume 31 Issue 1 Pages 38-47
The mesolimbic dopamine (DA) system is associated with pathogenesis of schizophrenia. We examined DA-containing neuronal structures of the ventral tegmental area (VTA) of 7 autopsy cases of schizophrenia aging from 24 to 78 (post-mortem period (PMI): 4-13 hours), and 5 control cases aging from 24 to 64 (PMI: 4-5 hour), using tyrosine hydroxylase (TH) immunohistochemistry. Three cases among schizophrenia group were leucotomized. A free floating method using 50-µm cryostat sections and three dimensional imaging analyzer AxioVision were applied to observe a wide range neuronal structures. In a case of a disorganized type (75-year-old female), TH-ir neuronal cell bodies in the VTA had an irregular shape and varied in sizes, and TH-ir nerve fibers were waved or formed straightened bundles running across each other. In a case of an undifferentiated-type (51-year-old female), the VTA contained various-sized TH-ir cell bodies, thick processes, and fibers having irregular thickness and a curved shape with many corners, when compared to controls with no detectable neuropsychiatric diseases. The VTA of a leucotomized case of a paranoid type (78-year-old female) contained TH-ir neurons of irregular shapes and various sizes, and also coiled-shaped or nappy fibers, suggesting wallerian degeneration. Morphological findings of TH-ir neurons differed between cases. The size of the VTA TH-ir cell bodies of the schizophrenia showed a tendency to be smaller than that of the controls. Generally, the VTA of schizophrenia contained morphologically heterogeneous TH-ir neurons of irregular shapes and various sizes, TH-ir fiber bundles, and straightened, curved or woven shaped fibers. The mechanisms underlying these characteristics of DA neurons of schizophrenia should be elucidated epigenetically as well as genetically.
