Publications by authors named "Isabel Benzel"

The mechanism of action of standard drug treatments for psychiatric disorders remains fundamentally unknown, despite intensive investigation in academia and the pharmaceutical industry. So far, little is known about the effects of psychotropic medications on brain metabolism in either humans or animals. In this study, we investigated the effects of a range of psychotropic drugs on rat brain metabolites.

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Haloperidol and olanzapine are widely used antipsychotic drugs in the treatment of schizophrenia and other psychotic disorders. Despite extensive research efforts within the biopharmaceutical industry and academia, the exact molecular mechanisms of their action remain largely unknown. Since the response of patients to existing medications can be variable and often includes severe side effects, it is critical to increase our knowledge on their mechanism of action to guide clinical usage and new drug development.

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Genetic studies have implicated the evolutionary novel, primates-specific gene locus G72/G30 in schizophrenia, bipolar and panic disorders. It encodes for a protein LG72 whose function has been controversially discussed as putative regulator of the peroxisomal enzyme D-amino-acid-oxidase (DAO), or as a mitochondrial protein, which promotes robust mitochondrial fragmentation in mammalian cell lines including human and rat primary neurons. Because of this conserved function we here have generated "humanized" BAC transgenic mice (G72Tg) expressing alternatively spliced G72 and G30 transcripts, and the LG72 protein.

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Background: Polymorphisms at the G72/G30 locus on chromosome 13q have been associated with schizophrenia or bipolar disorder in more than ten independent studies. Even though the genetic findings are very robust, the physiological role of the predicted G72 protein has thus far not been resolved. Initial reports suggested G72 as an activator of D-amino acid oxidase (DAO), supporting the glutamate dysfunction hypothesis of schizophrenia.

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The N-methyl-D-aspartate receptor co-agonist d-serine is synthesized by serine racemase and degraded by D-amino acid oxidase. Both D-serine and its metabolizing enzymes are implicated in N-methyl-D-aspartate receptor hypofunction thought to occur in schizophrenia. We studied D-amino acid oxidase and serine racemase immunohistochemically in several brain regions and compared their immunoreactivity and their mRNA levels in the cerebellum and dorsolateral prefrontal cortex in schizophrenia.

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Background: Evidence of genetic association between the NRG1 (Neuregulin-1) gene and schizophrenia is now well-documented. Furthermore, several recent reports suggest association between schizophrenia and single-nucleotide polymorphisms (SNPs) in ERBB4, one of the receptors for Neuregulin-1. In this study, we have extended the previously published associations by investigating the involvement of all eight genes from the ERBB and NRG families for association with schizophrenia.

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The membrane-bound acid phosphatase (MBAP), a Type I membrane protein predominantly associated with endosomal/lysosomal structures of Leishmania mexicana promastigotes, contains motifs in its cytosolic COOH-terminal tail (-MEVWRRYMKFKNKQSEAIIV-COOH) akin to tyrosine- and di-leucine-based sorting signals in multicellular organisms. Here, we first show that the COOH-terminal residues IIV of MBAP, but not the Y-residue, are required for endosomal targeting, suggesting specific binding to an adaptor complex at the cell surface. We then determine whether specific binding can be saturated by analysing the efficiency of endosomal targeting for increasing numbers of MBAP molecules per cell.

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