5HT2A and muscarinic receptors in schizophrenia: A post-mortem study

5. Neuropathology, Biochemistry

63

CA3 (15=0.042) and subiculum (p=0.002), with a similar trend in the parahippocampal gryus (p=0.07). VGLUT2 mRNA could not be analysed in the same way due to the low signal, and cellular in situ hybridisation measurements are thus underway. The VGLUTt data provide additional, independent evidence that synapses formed by hippocampal glutamatergic neurons are affected in schizophrenia. Acknowledgement: Supported by a Center Award from the Stanley Medical Research Institute.

S H A N K PROTEINS IN THE SUPERIOR TEMPORAL CORTEX OF PATIENTS WITH SCHIZOPHRENIA T. H a s h i m o t o , * N. K i t a m u r a , X. H. Lin, K. O k a m u r a , M. Yanagi, Y. K a j i m o t o , O. Shirakawa, K. M a e d a

Division of Psychiatry and Neurolog3; Department oJ" Environmental Health and Safety, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan Shank proteins (SH3 domain and ankyrin-repeat containing protein) have been recently identified as a family of scaffold proteins, and consist of three members: Shank 1, Shank 2 and Shank 3. Shank proteins are abundantly expressed in the brain and are mainly localized at postsynaptic sites in the neural synapses. Shank proteins and SAPAP (SAP 90/PSD-95-associated protein) are linked to the NMDA receptor-PSD-95 protein complex. Shank is also linked to the AMPA receptor and the metabotropic glutamate receptor. NMDA receptor antagonists such as phencyclidine can induce both positive and negative psychotic symptoms that are quite similar to schizophrenia in healthy volunteers, and they can also exacerbate these symptoms in patients with schizophrenia. Recently, increased mRNA expression of NMDA receptors and increased bindings of [3H]L689,560 to NMDA receptors have been reported in the superior telnporal cortex. Changes in PSD-95 expression have also been reported in some regions of the brains from patients with schizophrenia. Accordingly, abnormalities in NMDA receptor-mediated neurotransmission have been proposed as a major cause of the pathophysiology of schizophrenia. To examine whether changes in Shank proteins exist in patients with schizophrenia, in this study, we irnmunoquantified Shank 1, Shank 2 and Shank 3 using specific antibodies in the left and right superior temporal cortex (Brodmann's area 22) from the postmortem brains of patients with chronic schizophrenia. In off-drug patients with schizophrenia (patients receiving no neuroleptic treatment within three months of death), Shank 2 immunoreactivities in the right superior temporal cortex were significantly decreased, and Shank 1 and 3 immunoreactivities in the fight superior temporal cortex tended to be lower than the values in the control and on-drug groups (patients receiving neuroleptic treatment just before death). Shank 1, Shank 2 and Shank 3 immunoreactivities were significantly higher in the left side of the superior temporal cortex and tended to be higher in the fight side of the superior temporal cortex in the on-drug group than in the off-drug groups. There was no significant difference with respect to age, the time from death to autopsy or freezer storage time among the three groups. These changes in Shank proteins may indicate abnormal glutamatergic neurotransmission in the superior temporal cortex of patients with schizophrenia.

MISMATCH NEGATIVITY: EVIDENCE FOR AN NMDA-BASED DISORDER OF BRAIN PLASTICITY IN THE TEMPORAL AREA WHICH RELATES TO COGNITIVE DISTURBANCE IN SCHIZOPHRENIA S. R. Hirsch,* S. Krljes, T. B a l d e w e g

Psychiatry, Imperial College, London, England, United Kingdom Using the tissue from our prospectively assessed cohort of elderly institutionalised schizophrenic patients. We found two important findings which have subsequently been replicated in other centres. The first is a toss of dendritic spines on pyramidal cells in layer III of the superior temporal and pre-frontal areas which has now been confirmed by two other centres. The second is decreased gene expression for the NR-1 glutamate receptor in the superior temporal gyrus which was also found by the group at Mt Sinai. Both findings are consistent with the well-established findings of decreased cortical thickness and loss of pia without a loss of neuronal number and are consistent with the disconnectivity hypothesis of Friston, Frith and others. However our findings of decreased glutamate gene expression were more specific because we found a high correlation (r--0.91) between pre-morbidly assessed cognitive deficits in our patients and gene expression of NMDA-NR-1. Thus NR-1 predicted the cognitive deficit. Because Javitt had shown that an abnormality of an EEG evoked potential measure, Mismatch Negativity (MMN), depends on NR-1 function, we predicted that MMN amplitude would reflect the degree of cognitive dysfunction in younger patients with schizophrenia. We confirmed this hypothesis and have shown that these measures differentiate schizophrenics from hi-polar patients and patients with Alzheimer's. Moreover, we found that the cognitive deficiency is due to a failure of encoding of new information, i.e. cellular learning which was normal in patients with Alzheimer's disease. The ability of cells to adapt to new information is cNled 'cell plasticity' which we now think involves a glutamate disturbance underlying schizophrenia. Our evidence suggests that abnormality is in the temporal lobes.

5HT2A AND MUSCARINIC RECEPTORS IN SCHIZOPHRENIA: A POST-MORTEM STUDY Y. Inoue,* B. Dean, G. Pavey, S. Niwa, I. Matsumoto Department of Neuropsychiatry, Fukushima Medical University, Fukushima, Fukushima, Japan Several lines of evidence suggested possible changes in 5-HT2A and muscarinic MI, M4 receptors in various brain regions of schizophrenic subjects. To confirm the results from previous studies, we employed quantitative autoradiography to measure the number of these receptors in the dorsolateral prefrontal cortex (BA 9), the caudate/putamen and the hippocampal formation from the subjects with schizophrenia and normal control subjects. [3H]pirenzepine and [3H]ketanserin were used as ligands to label M1 plus M4, and 5HT2A receptors respectively. Six schizophrenic (diagnosed using DSN-IV) and six normal control brains were examined. There was a significant reduction in the specific binding of [3H]ketanserin in BA 9 from the schizophrenic subjects(p=0.036). No significant difference was observed in the specific binding of [3H]ketanserin in the caudate/putamen and the hippocampus between two groups. No significant difference was observed in the specific binding of [3H]pirenzepine in any of the regions examined. In the present study, region-specific and ligand-specific reduction in the density of 5HT2A receptor in the BA 9 fi'om schizophrenic subjects was

International Congress on Schizophrenia Research 2003

64

5. Neuropathology, Biochemistry

observed. This is the first study that confirmed the region selectivity and the ligand selectivity of the reduction of the 5-HT2A receptors in the subjects with schizophrenia by examining multiple brain regions from age- and sex-matched pairs. These findings support a possible involvement of a serotonergic system in the dorsolateral prefrontal cortex in the pathology of schizophrenia.

MOLECULAR

ABNORMALITIES

OF THE

HIPPOCAMPUS

IN SEVERE MENTAL ILLNESS:

POST-MORTEM

FINDINGS FROM THE

STANLEY NEUROPATHOLOGY

CONSORTIUM

M. B. Knable,* B. B. Bm'ci, J. J. Bartko, M. J. Webster, E. E Torrey Stanley Medical Research Institute, Bethesda, MD, USA Between 1994 and 2002, 48 data sets were returned from anterior hippocampal speciments from the Stanley Neuropathology Consortium. Data sets referable to the dentate gyms, CA1-CA4, and the subiculum, that contained at least 90% complete data, were selected for meta-analysis. When data for hippocampal subdivisions were counted separately, 224 variables were available for analysis. Missing data were imputed with a "hot-deck" procedure. The majority of data sets were not normally distributed. The entire set of markers was therefore tested with individual Kruskal-Wallis H tests. A DunnSidak correction for multiple comparisons was applied to the results. The data sets were also analyzed using the non-parametric classification and regression tree (CART) method. Two of the 224 variables revealed a significant difference between groups. The total number and density of parvalbumin labeled neurons in CA2 were decreased in schizophrenia samples(p<0.00t) relative to controls. The total number of parvalbumin labeled neurons was decreased in bipolar samples (p<0.04) relative to controls. Immuno-positive neurons for reelin were decreased in the molecular layer of the dentate gyms in schizophrenia (p=0.0002), bipolar disorder (p=0.004) and in depression (p=0.04). CART analysis with all four diagnostic groups revealed a maximum cmxet classification of 38% (p=0.016) with immuno-positive neurons for reelin in CA4 and immuno-positive neurons for SNAP-25 in the stratum oriens. Pair-wise CART analyses revealed significant maximal classifications between bipolar disorder and depression with SNAP-25 in stratum oriens, between bipolar disorder and schizophrenia with SNAP-25 in stratum oriens, and between bipolar disorder and normal controls with TrkA RNA in CA2 (p values <0.02). Depression was discriminated from normal controls by immuno-labeled neurons for reelin in CA4. The implications of these findings for the molecular neuropathology of severe mental illness will be discussed.

LOW GLYCOGEN

SYNTHASE

SCHIZOPHRENIA

- GENETIC MARKER

CONSEQUENCE

KINASE-3~ IN OR

OF NEURODEVELOPMENTAL

INSULT N. Kozlovsky,* C. Nadri, B. K. Lipska, D. R. Weinberger, C. Shannon-Weickert, J. E. Kleinman, R. H. Belmaker, G. A g a m Stanley Foundation Research Center, Ben-Gurion University, BeerSheva, Israel Glycogen synthase kinase-3 (GSK-3) is a protein kinase highly abundant in brain and involved in signal transduction cascades, particu-

larty neurodevelopment. Its activity and protein levels have recently been reported to be over 40% lower in postmortem frontal cortex of schizophrenic patients. GSK-3~3 in occipital cortex of schizophrenic patients was not reduced, suggesting regional specificity. There was no reduction in GSK-3~3 mRNA, protein levels or activity in fl:esh lymphocytes from schizophrenic patients. In the schizophrenia-related neonatal ventral hippocainpal lesion rat model we measured GSK3[3 protein levels and GSK-3 activity in the frontal cortex. GSK3~levels in lesioned rats were significantly lower than in sham rats, favoring perinatal insult as a cause of low GSK-3~3in schizophrenia. Taken together, these studies suggest that low GSK-3 in postmortembrain of schizophrenic patients is a late consequence of neurodevelopmental insult in schizophrenia and not a genetic marker of schizophrenia. In rats, acute or chronic cold restraint stress did not change GSK-3[~ protein levels, although functional GSK-3 activation is involved in the cellular stress response. Chronic treatment of rats with lithium, valproate, haloperidol or clozapine did not change rat cortical GSK-3~3 protein levels ex vivo, supporting the concept that low GSK-3[3 in schizophrenia is not secondary to stress or drug treatment. Our initial findings of low GSK-3[3 protein levels in postmortembrain have been replicated by another group. Our own group has found additionally that GSK-3[~ mRNA levels were 40% lower in postmortem DLPFC of schizophrenic patients, supporting ore"previous findings. An additional intriguing recent preliminary finding is that GSK-3[3 protein levels in CSF samples from schizophrenic patients are 28% lower than in control subjects. Further studies will be aimed at determining whether nonspecific neonatal damage or only specific factors cause low GSK-3 as a late effect. We plan to study whether low GSK-3[3 activity is associated with biochemical effects such as elevatedb~-catenin levels.

COMPLEMENT IMMUNE

SYSTEM AND CIRCULATING

COMPLEXES

SCHIZOPHRENIA:

UNDER

FAMILY STUDY

K. Mayilyan,* A. Boyajyan, S. Hakopyan, A. Soghoyan, R. B. Sire Institute of Molecular Biology of Al~nenian National Academy of. Sciences, Yerevan, Armenia The examination of families with positive history of schizophrenia is important for understanding the molecular pathomechanisms of this disorder. Using the blood samples of healthy volunteers (n=77), healthy and affected members (n=83) from three generations of twenty one families with positive history of schizophrenia we have tested classical pathway total complement (TCH) and C4 component haemolytic activities (CH50) and concentration of circulating immune complexes (CICs), as well as identified the protein components of these complexes by the use of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE). The percentage ratio of pathogenic CICs has been determined by using appropriate plotting method. Investigation of TCH activity did not reveal any significant difference between groups, whereas C4 component haemolytic activity of subjects with positive history of schizophrenia was sufficiently up regulate. In serum of schizophrenia affected members the mean concentration of small CICs was within a normal range, while concentration of gigantic, big and middle CICs were, correspondingly, 1.6, 1.8 and 1.9 times higher than data of controls (p<0.0001). It has been shown that 83.3% of immune complexes circulating in the blood of examined schizophrenic patients had pathogenic features. However, there were not difference between obtained data of schizophrenia-affected members and their healthy relatives. The SDS PAGE of C1Cs isolated from the blood of two big families'

International Congress on Schizophrenia Research 2003