Expression of the myristoylated alanine-rich C kinase substrate (MARCKS) and MARCKS-related protein (MRP) in the prefrontal cortex and hippocampus of suicide victims

BACKGROUND

Although suicide is a leading cause of death in the United States and represents a significant public health threat, little is known about the neurobiological or molecular factors that contribute to its pathophysiology. A number of studies now indicate that lithium has considerable efficacy in the prevention of suicide in patients with affective disorders, and accumulating evidence indicates that protein kinase C (PKC) and its substrates, in particular the myristoylated alanine-rich C kinase substrate (MARCKS), are primary targets of chronic lithium treatment. We therefore hypothesized that a dysregulation in MARCKS expression in key brain regions could contribute to the pathophysiology associated with suicide. To address this, we examined MARCKS, as well as the closely related MARCKS-related protein (MRP), mRNA expression in the hippocampus and dorsolateral prefrontal cortex of suicide victims and normal controls.

METHOD

MARCKS and MRP mRNA expression was assessed by quantitative in situ hybridization histochemistry performed on postmortem hippocampal and dorsolateral prefrontal cortex sections from suicide (N = 9) and normal control (N = 10) brains.

RESULTS

In the normal hippocampus, both MARCKS and MRP mRNA expression were highest in the granule cell layer and low-moderate in CA1, CA3, and hilus. A high level of MRP mRNA expression was also observed in the white matter of the fimbria/fornix. Neither MARCKS nor MRP mRNA expression levels differed significantly in the granule cell layer, CA3, hilus, or CA1 in suicide victims relative to normal controls (1-way ANOVA, p > .05). In the normal prefrontal cortex, MARCKS was expressed exclusively in gray matter (layers I-VI), whereas MRP was expressed in both gray and white matter. Neither MARCKS nor MRP mRNA expression levels in the gray and white matter regions of the dorsal prefrontal cortex differed between suicides and normal controls (1-way ANOVA, p > .05).

CONCLUSION

The present findings are the first to demonstrate the expression and distribution of MARCKS and MRP in the human hippocampus and dorsolateral prefrontal cortex, and their expression pattern within these regions bears strong resemblance to those observed in the adult rat brain. Comparison of MARCKS and MRP mRNA expression in the hippocampus and prefrontal cortex of suicide victims and normal controls indicates that these 2 mRNAs are not differentially regulated in these regions. However, differences in MARCKS and MRP protein expression and function cannot be ruled out by the present findings.

The transformation of everyday social experience: what a mental and social health perspective reveals about Chinese communities under global and local change

Chinese communities in East Asia are undergoing great economic and social change. The result includes material prosperity but also worsening mental and social health indices. Epidemiological studies clarify the magnitude of these problems and the particular vulnerability of women and the elderly. Ethnographic studies indicate that moral experience is also changing, and that with it subjectivity is being altered in ways that are of concern. And yet it is not clear, in historical perspective, how to assess these changes when they are compared to the extraordinarily difficult experiences of the Chinese over most of the Century.

Alpha 2 isoform of the Na,K-adenosine triphosphatase is reduced in temporal cortex of bipolar individuals

BACKGROUND

The pathophysiology of bipolar illness has been associated with changes in transmembrane ion flux and redistribution of biologically active ions. The recent identification of multiple isoforms of Na,K-adenosine triphosphatase (ATPase) alpha and beta subunits raises the possibility of altered pump isoform expression.

METHODS

We determined Na,K-ATPase alpha subunit expression in postmortem temporal cortex gray matter from individuals suffering from bipolar disorder, schizoaffective disorder, schizophrenia, and matched normal controls. Quantification of isoform expression was accomplished via densitometric scanning of Western blots utilizing isoform-specific antibodies.

RESULTS

Bipolar individuals exhibited a significant reduction in the abundance of the alpha 2 isoform of Na,K-ATPase compared to normal controls. Schizophrenic and schizo-affective brains were not significantly different from normal controls.

CONCLUSION

These data suggest that previously observed abnormalities in regulation and distribution of ions in bipolar illness may be related to specific alpha 2 dysregulation.

VASE-containing N-CAM isoforms are increased in the hippocampus in bipolar disorder but not schizophrenia

The neural cell adhesion molecule (N-CAM) is a cell recognition molecule that is involved in cellular migration, synaptic plasticity, and CNS development. In schizophrenia, a 105- to 115-kDa N-CAM protein is increased in CSF and in the hippocampus and prefrontal cortex. The variable alternatively spliced exon (VASE) of N-CAM is developmentally regulated and can be spliced into any of the major 120-, 140-, and 180-kDa N-CAM isoforms. We determined that the variable alternative spliced exon of N-CAM (VASE) also is increased in bipolar disorder by quantitative Western immunoblot. VASE immunoreactive proteins (triplet bands around 140 kDa and a single band around 145 kDa) were identified in soluble and membrane brain extracts and quantified in the hippocampus. Soluble VASE 140 kDa was increased in the hippocampus of patients with bipolar disorder as compared to controls, patients with schizophrenia, and suicide cases. Membrane-extracted VASE 140 and 145 kDa were unchanged in the same groups. Multiple 145-kDa VASE-immunoreactive proteins that also reacted to an N-CAM antibody were separated by isoelectric focusing and electrophoresis followed by western immunoblotting; however, the VASE 140-kDa proteins were only weakly N-CAM immunoreactive. By immunohistochemistry, VASE colocalized with GFAP-positive astrocytes in the hippocampus. VASE immunostaining was also observed in the cytoplasm of CA4 pyramidal neurons that were positive for phosphorylated high molecular weight neurofilament and synaptophysin terminals. Thus no differences in VASE were found in patients with schizophrenia, but there was a marked increase of VASE immunoreactive proteins in bipolar disorder. It is possible that abnormal regulation of N-CAM proteins results in differing patterns of abnormal expression in neuropsychiatric disorders.

The neuroanatomy and neurochemistry of schizophrenia

Substantial progress, in part owing to recent refinements in methodology, has been made in unraveling the anatomic correlates of schizophrenia. Subtle pathomorphologic changes, distinct from those of well-known degenerative brain disorders, have been observed. Neurochemical characterization has illuminated the nature of these morphologic abnormalities and has pointed to complex dysregulation of neurotransmitters and G proteins. New biochemical hypotheses such as the glutamate hypothesis have replaced and revitalized more established concepts in the neurochemistry of schizophrenia.

Abnormal expression of cell recognition molecules in schizophrenia

Schizophrenia is a neuropsychiatric disorder of unknown etiology associated with subtle changes in brain morphology. The cell recognition molecules (CRMs) neural cell adhesion molecule (N-CAM) and L1 are involved in morphoregulatory events and numerous neurodevelopmental processes. We found a selective increase of 105- to 115-kDa N-CAM in the hippocampus and prefrontal cortex of patients with schizophrenia while other N-CAM isoforms and L1 proteins were not altered. There was also evidence for an abnormality in CRM expression in schizophrenic patients: concentrations of 200-kDa L1 were strongly correlated with expression of N-CAM isoforms and cleaved L1 proteins in controls, whereas these correlations were absent in patients with schizophrenia. The increase of the 105- to 115-kDa N-CAM isoform in the brains of patients with schizophrenia confirms previous cerebrospinal fluid findings. Increased N-CAM in schizophrenia may result from structural brain abnormalities, from glial processing of N-CAM, or from an aberration in the regulation of N-CAM expression.

Neuropathology of suicide. A review and an approach

Neuropathology is one approach to the effort to elucidate the pathophysiology of suicide. Initial neurochemical studies focusing on the roles of serotonin (5-HT) and noradrenaline (NE) abnormalities in brains of suicide victims have been somewhat inconsistent. More recently developed methodologies, including quantitative receptor autoradiography, immunoblotting, immunohistochemistry, cell morphometry, in situ hybridization, Northern analysis, solution hybridization/RNase protection assay, reverse transcriptase polymerase chain reaction, and genotyping, which have already been applied successfully in studies of other disorders of brain structure or function, are now increasingly being adopted for postmortem studies of suicide. These new strategies are adding convergent evidence for brain 5-HT and NE dysfunction in the etiology of suicide susceptibility, refining the neuroanatomical localization of this dysfunction, and in addition, implicating heretofore unsuspected candidate neurotransmitter systems in the neuropathological substrates of suicide susceptibility. It is argued here that the confluence of the availability of suitable postmortem samples and this augmentation of our armamentarium of techniques promises the attainment of important new insights into the biological underpinnings of suicide from postmortem research. It is to be hoped that this new knowledge might inspire novel pharmacotherapeutic strategies for the prevention of suicide.

A qualitative and quantitative analysis of the entorhinal cortex in schizophrenia

The entorhinal cortex (ERC) has been implicated in schizophrenia by a number of studies. There is anatomical observation of neuronal heterotopias in the rostral ERC, which is consistent with a hypothesis of neurodevelopmental abnormalities in this disease. In view of the significant cytoarchitectonic variation of the ERC throughout its rostro-caudal extent, we performed a detailed subareal analysis of the rostral two-thirds of the entorhinal cortex (ERCr) in 14 postmortem schizophrenic brains and 14 matched controls (mean ages of 48 and 47 respectively). This systematic evaluation included both a qualitative microscopic analysis of morphogenetic anomalies that would be consistent with neurodevelopmental pathology and quantitative measurements of total neuronal number, average neuronal density, laminar volume and laminar depth from the cortical surface in cytoarchitectonically matched subareas of schizophrenic and control brains. Parcellation of the entire ERC on the basis of cytoarchitectonic criteria identified five distinct regions, similar to those described in the macaque, except that in the human brain three of the regions were further divisible into two or three subareas, yielding nine distinct cellular compartments. Five rostral areas, prorhinal (Pr), lateral (28L), intermediate rostral and caudal (281r and 281c), and sulcal (28S), comprise the ERCr. Gross and microscopic examination of these subdivisions throughout the ERCr failed to reveal laminar disorganization in any of the schizophrenic brains. The brains also did not differ significantly with respect to total neuronal number, total volume and neuronal density per laminar and subareal subdivision, or laminar thickness per entorhinal subarea. However, neuronal number and density were reduced by 12-18% in Pr and 28L, suggesting that mild quantitative abnormalities may exist in the ERCr and might possibly be revealed in a larger sample of schizophrenic brains. We have failed to confirm previous reports of laminar disorganization in the ERCr in brains of patients with schizophrenia; to the extent that this region is implicated in schizophrenia, the structural changes are likely to consist of more subtle cellular disturbances.

Glutamate receptors in the postmortem striatum of schizophrenic, suicide, and control brains

INTRODUCTION

Previous postmortem studies of glutamate receptors and uptake sites have shown decreased D-aspartate (D-Asp) (a marker for the high affinity glutamate uptake site) and elevated (+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d]cyclohepten-5,10-imine maleate (MK-801) binding in the putamen in schizophrenia and elevated alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor binding in the caudate nucleus of schizophrenics who committed suicide. The relative effects of schizophrenia, suicide, and neuroleptic treatment in these findings is unclear. This study further explores binding to glutamate receptors (NMDA, kainic acid, and AMPA) and uptake sites in postmortem striatal structures in schizophrenics relative to three control groups (normal controls, neuroleptic-treated controls, and nonpsychotic suicides).

METHODS

We compared the binding densities of tritium-labeled ligands 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), kainic acid (KA), MK-801, and D-Asp, which target the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), KA, and N-methyl-D-aspartic acid (NMDA) ionotropic receptor sites and the glutamate uptake site, respectively, in postmortem striatal/accumbens tissue from six DSM-III-R schizophrenics, eight normal controls, eight neuroleptic-treated controls, and eight suicide victims using standard receptor autoradiographic methods.

RESULTS

Binding of [3H] CNQX (AMPA receptors) was significantly different among the four groups across the subdivisions of the striatum: caudate, putamen, and nucleus accumbens (ANOVA P = .0007, .002, and .004, respectively). The schizophrenia group had higher mean CNQX binding in the caudate nucleus than normal (P = .005) and neuroleptic controls (P = .006) but not suicides (P = .6), who were also higher than normals and neuroleptic-treated controls (P = .05). The binding densities of tritiated MK-801, KA, and D-Asp were not significantly different among the four groups of subjects in any of the striatal regions examined.

CONCLUSIONS

The data suggest there may be an increased density of AMPA receptor sites in the caudate nucleus in schizophrenia that is not apparently due to neuroleptic treatment. A similar increase was also seen the suicide group. Although these data do not confirm previous reports of an increase in [3H]MK-801 or a decrease in [3H]D-Asp binding in the basal ganglia in schizophrenia, the increased caudate AMPA binding observed here could reflect decreased cortical glutamatergic innervation of the caudate. Its implication for suicide is unclear.

Prodynorphin mRNA expression is increased in the patch vs matrix compartment of the caudate nucleus in suicide subjects

Experimental and clinical studies suggest an involvement of the opioid neuropeptide system in psychiatric disorders. Notably, opioid peptide immunoreactivity is altered in the cerebrospinal fluid of chronic schizophrenics and manic-depressive subjects. Despite these clinical findings, few postmortem investigations have examined the association of endogenous opioid neuropeptides with schizophrenia and suicide. Anatomically, a tight interaction exists within the neostriatum between the opioid peptide (dynorphin and enkephalin) system and classical neurotransmitters such as dopamine which has been implicated in both the psychotic symptoms and the cognitive deficits that characterize schizophrenia (see review). The neostriatum is differentially organized into patch and matrix neurochemical mosaic compartments anatomically connected to limbic- and sensorimotor-related brain regions, respectively. Moreover, the human neostriatum is characterized by a heterogenous expression of the prodynorphin opioid gene: high in the patch, but low in the matrix compartment. The present results show for the first time a differential alteration of prodynorphin within distinct striatal compartments in postmortem tissue from nonschizophrenic suicide subjects. The prodynorphin patch/matrix mRNA expression was elevated in the caudate nucleus of suicide subjects as compared to normal controls and schizophrenics in which no alterations in opioid peptides or D1 and D2 mRNA expression were apparent. Altogether the findings suggest that discrete dysfunction of the endogenous opioid dynorphin system might contribute to depression and the risk of suicide in nonschizophrenic subjects.

Reduced frontal cortex inositol levels in postmortem brain of suicide victims and patients with bipolar disorder

OBJECTIVE

This study aimed to evaluate aspects of second messenger function in the brain of suicide victims and patients with bipolar disorder.

METHOD

Inositol and its synthetic enzyme, inositol monophosphatase, were measured in postmortem brain samples of 10 suicide victims, eight patients with bipolar affective disorder, and 10 normal comparison subjects.

RESULTS

The frontal cortex inositol levels of the suicide victims and the patients with bipolar disorder were significantly less than those of the normal comparison group. No differences in cerebellum or occipital cortex inositol levels were found among the three groups. The groups also showed no differences in inositol monophosphatase activity in any brain area.

CONCLUSIONS

These results could suggest a deficiency of second messenger precursor in patients with bipolar disorder and suicide victims.

Abnormal cholecystokinin mRNA levels in entorhinal cortex of schizophrenics

Limbic cortical regions, including anterior cingulate cortex (ACC), prefrontal cortex (PFC) and entorhinal cortex (ERC), have been implicated in the neuropathology of schizophrenia. Glutamate projection neurons connect these limbic cortical regions to each other, as well as to the terminal fields of the striatal/accumbens dopamine neurons. Subsets of these glutamate projection neurons, and of the GABA interneurons in cortex, contain the neuropeptide cholecystokinin (CCK). In an effort to study the limbic cortical glutamate projection neurons and GABA interneurons in schizophrenia, we have measured CCK mRNA with in situ hybridization histochemistry in postmortem samples of dorsolateral (DL)PFC, ACC and ERC of seven schizophrenics, nine non-psychotic suicides and seven normal controls. CCK mRNA is decreased in ERC (especially layers iii vi) and subiculum in schizophrenics relative to controls. Cellular analysis indicates that there is a decrease in density of CCK mRNA in labelled neurons. In so far as ERC CCK mRNA is not reduced in rats treated chronically with haloperidol, this decrease in schizophrenics does not appear to be related to neuroleptic treatment. In contrast, in DLPFC, where schizophrenics do not differ from normals, the suicide victims have elevated CCK mRNA (especially in layers v and vi), and increased cellular density of CCK mRNA, relative to both normals and schizophrenics. These results lend further support for the involvement of ERC and hippocampus in schizophrenia, suggesting that neurons that utilize CCK may be particularly important. Similarly, an increase in CCK mRNA levels in the PFC of suicides adds to a growing body of evidence implicating this structure in this pathological state. In so far as CCK is co-localized with GABA or glutamate in cortical neurons, both of these neuronal populations need to be studied further in schizophrenia and suicide.

A postmortem study of frontal cortical dopamine D1 receptors in schizophrenics, psychiatric controls, and normal controls

We tested the hypothesis that aberrant dopaminergic innervation in frontal and cingulate cortices of schizophrenic patients might be revealed by examining dopamine D1 receptor density in these brain regions. A quantitative autoradiographic assay with [3H]-SCH 23390 was performed with samples from schizophrenic patients, normal controls, neuroleptic-treated controls, and suicides. There was a significant elevation in specific binding of [3H]-SCH 23390 in the intermediate layer of the prefrontal cortex from neuroleptic-treated controls (p = .05). Elevated [3H]-SCH 23390 binding in several layers from prefrontal and cingulate cortex was observed in schizophrenic subjects, although these results did not reach statistical significance. When data from subjects who had received neuroleptics (schizophrenics and neuroleptic controls) were compared to subjects who had not received neuroleptics (normal controls and suicides), there was a significant elevation in receptor density in both the prefrontal (p = .05) and cingulate cortices (p = .03). These data suggest that elevated [3H]-SCH 23390 binding in human prefrontal and cingulate cortices may occur with chronic neuroleptic treatment, although increased receptor density that may exist as a feature of psychotic illnesses cannot be excluded.

Different side effect profiles of risperidone and clozapine in 20 outpatients with schizophrenia or schizoaffective disorder: a pilot study

OBJECTIVE

The purpose of this study was to compare the side effect +profiles of clozapine and risperidone.

METHOD

The subjects were 20 outpatients with schizophrenia or schizoaffective disorder who were clinically stable on a regimen of clozapine at the time of screening. They underwent a randomized-order crossover comparison of 6 weeks of risperidone treatment and 6 weeks of clozapine treatment. Clinical and neurocognitive variables were assessed by raters blind to medication status, and severity of side effects was determined from patients' self-reports.

RESULTS

Side effect measures, but not clinical ratings, were significantly different after 6 weeks of treatment with the two drugs. Patients required more benztropine for motor effects and complained of more insomnia with risperidone and more sedation with clozapine. Body weight was higher at the end of clozapine treatment than at the end of risperidone treatment.

CONCLUSIONS

In this exploratory study, the side effect profiles of clozapine and risperidone were consistent with the different pharmacodynamic profiles of the two drugs.

Possible relationship between conditions associated with chronic hypoxia and brain mitochondrial DNA deletions

The brain relies heavily on aerobic metabolism which requires functional mitochondria. Mitochondria are subcellular organelles with their own genome which codes for 13 essential protein subunits. By employing PCR assays to examine brain tissue from 43 age-comparable individuals (between ages 34 and 73), we found a correlation between mitochondrial DNA deletion mutations, mtDNA4977 deletions, and conditions associated with chronic hypoxia. In prior studies, utilizing only 6 to 12 clinical samples, mtDNA4977 deletions were reported to increase in specific regions of the brain with aging. However, we found 12-fold and 5-fold higher levels of mtDNA4977 deletions in the putamen and the superior frontal gyrus of the cortex, respectively, from individuals who had conditions associated with chronic hypoxia when compared with individuals without evidence of such conditions. These findings suggest that chronic hypoxia should be more closely examined in the pathophysiology of central nervous system diseases.

Analysis of the DRPLA triplet repeat in brain tissue and leukocytes from schizophrenics

An expansion of the CAG triplet in the human gene called atrophin-1 or CTG-B37 causes the neuropsychiatric disease known as dentatorubral-pallidoluysian atrophy (DRPLA). We have examined the genomic DNA from brains and peripheral blood leukocytes (PBLs) of schizophrenic and non-schizophrenic individuals and PBLs from a cohort of monozygotic twins discordant or concordant for schizophrenia, for expansions of the CTG-B37 region. All samples, including non-schizophrenic/normal controls, had 7-22 CAG repeats in this region. Thus we found no evidence for an expansion of the DRPLA triplet repeat associated with schizophrenia when compared to controls. Our data suggest that an expansion in the CTG-B37 gene is not linked to or responsible for the disease schizophrenia.

The neuropathology of schizophrenia

Neuropharmacologic discoveries have driven much of the research on neural substances of schizophrenia since the advent of neuroleptic drugs, which appear to share blockade of dopamine receptors. as their common denominator. Yet, despite concerted efforts to identify the source of putative dopaminergic hyperactivity in the brain in schizophrenia, definitive evidence for the "dopamine hypothesis of schizophrenia" remains elusive. More recently, a "neural systems" approach, focussing on the limbic system, has yielded substantial convergent evidence, from both in vivo imaging and postmortem morphological, biochemical, and molecular biological methods, implicating limbic cortex in the neuropathology underlying schizophrenia. Moreover, these limbic cortical regions modulate dopaminergic function in the striatum and nucleus accumbens, via glutamatergic projections. Increasingly, focus is shifting to a role for glutamatergic dysfunction in schizophrenia, opening the possibility that drugs that act upon glutamate function, either directly or indirectly via co-modulators of glutamate transmission, could potentially be developed as adjunctive or primary novel pharmacotherapeutic strategies.

Search for viral nucleic acid sequences in brain tissues of patients with schizophrenia using nested polymerase chain reaction

BACKGROUND

We used polymerase chain reaction to search for nucleic acid sequences of several viruses in DNA and RNA extracted from brain tissues of schizophrenic and control subjects.

METHODS

We extracted DNA and RNA templates from frozen brain specimens of 31 patients with schizophrenia and 23 nonschizophrenic control patients with other diseases. The extracts were subjected to polymerase chain reaction with oligonucleotide primers for 12 different viruses (cytomegalovirus, Epstein-Barr virus, herpes simplex virus type 1, human herpesvirus type 6, varicellazoster virus, measles virus, mumps virus, rubella virus, the picornavirus group, influenza A virus, human T-cell lymphotropic virus type I, and St Louis encephalitis virus), several of which have been suspected of involvement in schizophrenia. Nested primers were used to increase the sensitivity of the method.

RESULTS

No amplified nucleic acid sequences encoded by the selected viral genomes were detected in extracts of any brain specimens from either schizophrenic or control patients.

CONCLUSIONS

These data agree with previous studies that failed to find sequences of a number of viruses in the cerebrospinal fluid or selected areas of the brains of schizophrenic patients. Additional efforts should be undertaken to identify other known and unknown pathogens in schizophrenia, sampling more areas of the brain from subjects with a variety of clinical types of schizophrenia.

Abnormal excitatory neurotransmitter metabolism in schizophrenic brains

BACKGROUND

Schizophrenia has been hypothesized to be caused by a hypofunction of glutamatergic neurons. Findings of reduced concentrations of glutamate in the cerebrospinal fluid of patients with schizophrenia and the ability of glutamate-receptor antagonists to cause psychotic symptoms lend support to this hypothesis. N-acetylaspartylglutamate (NAAG), a neuropeptide that is highly concentrated in glutamatergic neurons, antagonizes the effects of glutamate at N-methyl-D-aspartate receptors. Moreover, NAAG is cleaved to glutamate and N-acetylaspartate by a specific peptidase, N-acetyl-alpha-linked acidic dipeptidase (NAALADase). To test the glutamatergic hypothesis of schizophrenia, we studied the NAAG-related glutamatergic variables in postmortem brains from patients with schizophrenia, neuroleptic-treated controls, and normal individuals, with particular emphasis on the prefrontal cortex and hippocampus.

METHOD

Different regions of frozen brain tissue from three different groups (patients with schizophrenia, neuroleptic-treated controls, and normal controls) were assayed to determine levels of NAAG, N-acetylaspartate, NAALADase, and several amino acids, including aspartate and glutamate.

RESULTS

Our study demonstrates alterations in brain levels of aspartate, glutamate, and NAAG and in NAALADase activity. Levels of NAAG were increased and NAALADase activity and glutamate levels were decreased in the schizophrenic brains. Notably, the changes in NAAG level and NAALADase activity in schizophrenic brains were more selective than those for aspartate and glutamate. In neuroleptic-treated control brains, levels of aspartate, glutamate, and glycine were found to be increased.

CONCLUSIONS

The changes in levels of aspartate, glutamate, NAAG, and NAALADase are prominent in the prefrontal and hippocampal regions, where previous neuropathological studies of schizophrenic brains demonstrate consistent changes. These findings support the hypothesis that schizophrenia results from a hypofunction of certain glutamatergic neuronal systems. They also suggest that the therapeutic efficacy of neuroleptics may be related to increased glutamatergic activity.

The social course of epilepsy: chronic illness as social experience in interior China

Findings are reported from a collaborative research project on the experience of epilepsy and treatment among patients and family members in Shanxi and Ningxia Provinces in China. Family, marriage, financial and moral consequences of the social experience of epilepsy support the conceptualization of chronic illness as possessing a social course. Beyond traditional concern with stigma, application of concepts of delegitimation, sociosomatic processes, coping as resistance, contestation in the evaluation of efficacy and compliance, and the cultural ontology of suffering illustrate other ways that social theory is useful in research on chronic illness and disability.

Persistent catalepsy associated with severe dyskinesias in rats treated with chronic injections of haloperidol decanoate

Patients who develop persistent parkinsonism while on chronic neuroleptic therapy may be predisposed towards the development of tardive dyskinesia (TD). We investigated this issue in an animal model of TD by examining the association between catalepsy and the syndrome of neuroleptic-induced vacuous chewing movements (VCMs). VCMs were measured every 3 weeks for 33 weeks while rats received injections of haloperidol decanoate. Catalepsy was measured after the second through the seventh injections of the depot neuroleptic. There were no correlations between the severity of catalepsy scores after the second or third injections of haloperidol and the severity of the overall VCM syndrome. However, the severity of the catalepsy score following the third through seventh injections of haloperidol strongly correlated with the concurrent number of VCMs. Persistent high catalepsy scores across the six catalepsy rating sessions were strongly associated with the development of persistent severe VCMs. These findings suggest that, to the extent that persistent parkinsonian signs in humans are associated with a propensity towards the development of TD, the VCM syndrome in rats is at least a partially faithful animal model of this relationship.

Distribution of putative D4 dopamine receptors in postmortem striatum from patients with schizophrenia

The identification of five dopamine receptor subtypes has given the dopamine hypothesis of schizophrenia new life. The D4 receptor is particularly intriguing because it binds clozapine with high affinity. Putative D4 receptors were labeled in postmortem human brain by subtracting the binding of a saturating concentration of 3H-raclopride (6 nM, which labels D2 and D3 receptors) from that labeled by a saturating concentration of [3H]YM 09151-2 (1-1.3 nM, which labels D2, D3, and D4 receptors). In the control brain, putative D4 receptors show a homogenous distribution in striatum and nucleus accumbens. This is also true in schizophrenic brains, although the levels are significantly higher (twofold). These data are inconsistent with mRNA studies that have shown negligible amounts in striatum and accumbens, with modest amounts reported in most of cerebral cortex. These findings suggest that the putative D4 receptors are not synthesized in this region, but are presynaptically localized on striatal afferent terminals. Our findings confirm and extend the report of Seeman et al. (1993). Extension of these findings into the nucleus accumbens is important because of its extensive connections to the limbic system while the putamen is exclusively "motor" striatum.