Publications by authors named "Toshikazu Kakizaki"

Patients with glioma often demonstrate epilepsy. We previously found burst discharges in the peritumoral area in patients with malignant brain tumors during biopsy. Therefore, we hypothesized that the peritumoral area may possess an epileptic focus and that biological alterations in the peritumoral area may cause epileptic symptoms in patients with glioma.

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GABA is a major neurotransmitter in the mammalian central nervous system. Glutamate decarboxylase (GAD) synthesizes GABA from glutamate, and two isoforms of GAD, GAD65, and GAD67, are separately encoded by the Gad2 and Gad1 genes, respectively. The phenotypes differ in severity between GAD single isoform-deficient mice and rats.

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Gene expression programs and concomitant chromatin regulation change dramatically during the maturation of postmitotic neurons. Subnuclear positioning of gene loci is relevant to transcriptional regulation. However, little is known about subnuclear genome positioning in neuronal maturation.

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  • * Researchers created a mouse model with reduced GAD67 levels that can survive to adulthood, allowing for the study of GAD67's role in mature brains.
  • * GAD67 knockdown mice showed increased movement and impaired emotional responses, indicating that decreased GAD67 might lead to emotional problems similar to those found in psychiatric disorders.
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GABAergic dysfunctions have been implicated in the pathogenesis of schizophrenia, especially the associated cognitive impairments. The GABA synthetic enzyme glutamate decarboxylase 67-kDa isoform (GAD67) encoded by the GAD1 gene is downregulated in the brains of patients with schizophrenia. Furthermore, a patient with schizophrenia harboring a homozygous mutation of GAD1 has recently been discovered.

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GABA is synthesized by glutamate decarboxylase (GAD), which has two isoforms, namely, GAD65 and GAD67, encoded by the Gad2 and Gad1 genes, respectively. GAD65-deficient (Gad2 ) mice exhibit a reduction in brain GABA content after 1 month of age and show spontaneous seizures in adulthood. Approximately 25% of Gad2 mice died by 6 months of age.

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  • The striatum is crucial for connecting brain cortex activity to output from the basal ganglia, with striatal neurons showing slow calcium oscillations linked to the signaling pathway involving mGluR5 and IP3R.
  • Striatal neurons can maintain calcium levels for long periods, but the specific role of store-operated calcium channels (SOCCs) in these neurons is not well understood.
  • This study finds that SOCCs are important for calcium signaling in striatal GABAergic neurons, and inhibiting SOCCs reduces the frequency of these slow calcium oscillations, suggesting their role in maintaining calcium concentrations.
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Major depressive disorder (MDD) is a highly prevalent psychiatric disorder worldwide. Several lines of evidence suggest that the dysfunction of somatostatin (SOM) neurons is associated with the pathophysiology of MDD. Importantly, most SOM neurons are γ-aminobutyric acid (GABA) interneurons.

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Glycine is an inhibitory neurotransmitter in the brainstem and spinal cord. Glycine transporter 2 (GLYT2) is responsible for the uptake of extracellular glycine. GLYT2 is specifically expressed in glycinergic neurons and thus has been used as a marker of glycinergic neurons.

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Decreased expression of the GABA synthetic enzyme glutamate decarboxylase 67 (GAD67) in a subset of GABAergic neurons, including parvalbumin (PV)-expressing neurons, has been observed in postmortem brain studies of schizophrenics and in animal models of schizophrenia. However, it is unclear whether and how the perturbations of GAD67-mediated GABA synthesis and signaling contribute to the pathogenesis of schizophrenia. To address this issue, we generated the mice lacking GAD67 primarily in PV neurons and characterized them with focus on schizophrenia-related parameters.

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  • * Researchers created a mouse model with VGAT specifically knocked out in Purkinje cells (L7-VGAT mice) and found that, despite similar cerebellar structures to control mice, these mice had significant issues with motor coordination.
  • * The study suggests that while VGAT is not critical for maintaining cerebellar structure, it is vital for smooth motor function, making the L7-VGAT mouse model valuable for investigating the relationship between Purkinje cells, at
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Background: The vesicular GABA transporter (VGAT) loads GABA and glycine from the neuronal cytoplasm into synaptic vesicles. To address functional importance of VGAT during embryonic development, we generated global VGAT knockout mice and analyzed them.

Results: VGAT knockouts at embryonic day (E) 18.

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GluN2B (GluRepsilon2/NR2B) subunit is involved in synapse development, synaptic plasticity, and cognitive function. However, its roles in synaptic expression and function of NMDA receptors (NMDARs) in the brain remain mostly unknown because of the neonatal lethality of global knock-out mice. To address this, we generated conditional knock-out mice, in which GluN2B was ablated exclusively in hippocampal CA3 pyramidal cells.

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