Immunohistochemical study of vesicle monoamine transporter 2 in the hippocampal formation of PCP-treated mice.

The exact pathophysiology of schizophrenia is unknown despite intensive scientific studies using molecular biology, psychopharmacology, neuropathology, etc. It is thought that neurodevelopmental failures such as neuronal network incompetence and the inappropriate formation of neurons affect the neurotransmitters. Several animal models have been created to investigate the etiology of this disease. In this study, we investigated the expression of vesicle monoamine transporter 2 (VMAT2), which has a significant role in neurotransmission, in the hippocampal formation in 1-phenylcyclohexylpiperazine (PCP)-treated mice using immunohistochemical staining technique to clarify neuronal abnormalities. PCP-treated mice are thought to be one of novel animal models for schizophrenia. The expression of VMAT2 in the hippocampal formation was significantly reduced overall in the PCP-treated mice compared to that in control (saline-treated) mice, also these reductions were observed throughout the brain. These facts implied that the pathophysiology of this disease involves abnormal monoaminergic transmission through VMAT2, despite PCP was the N-methyl-d-aspartate (NMDA) receptor antagonist that might induce glutamatergic abnormality. Since insufficient or excess release of neurotransmitter might alter neurochemical function and neurotransmission, VMAT2 might be an important target for biological research in psychiatric disease including schizophrenia.