Microtubule-associated protein MAP2 expression in olfactory bulb in schizophrenia

Previous studies have described alterations in presynaptic and postsynaptic elements in various parts of the CNS in schizophrenia, which may, at least in part, be due to abnormalities in neurodevelopmental processes. The olfactory bulb (OB) is a unique CNS area for examining synaptic development and plasticity in schizophrenia because it undergoes continuous reinnervation throughout life. Moreover, olfactory deficits and reduced OB volume have been observed in schizophrenia. We investigated the expression in the OB of the microtubule-associated protein MAP2, which has been shown to be abnormally expressed in the hippocampal region in schizophrenia. In both developing and mature neurons, MAP2 is an important structural component of dendrites and participates in the modification of synaptic organization. We used immunocytochemistry with phosphoepitope-specific and phosphorylation-state-independent antibodies to examine MAP2 expression in the glomerular layer of the OB in elderly subjects with chronic schizophrenia and controls. Phosphorylation-independent MAP2 expression was significantly reduced in schizophrenia, while phosphorylated MAP2 expression did not differ between groups. These results are consistent with faulty OB innervation in schizophrenia.