Publications by authors named "Hiromitsu Shimizu"

Accumulating evidence suggests that the pathologic lesions of schizophrenia may in part be due to the altered cytoskeletal architecture of neurons. Microtubule-associated proteins (MAPs) that bind to cytoskeletal microtubules to stabilize their assembly are prominently expressed in neurons. Of the MAPs, MAP6 (STOP) has a particular relevance to schizophrenia pathology, since mice deficient in the gene display neuroleptic-responsive behavioral defects.

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Background: Primary polydipsia is a common complication in patients with chronic psychoses, particularly schizophrenia. Disease pathogenesis is poorly understood, but one contributory factor is thought to be dopamine dysregulation caused by prolonged treatment with neuroleptics. Both angiotensin-converting enzyme (ACE) and orexin (hypocretin) signaling can modulate drinking behavior through interactions with the dopaminergic system.

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The increased incidence of minor physical anomalies (MPAs) in schizophrenia is the fundamental basis for the neurodevelopmental hypothesis of schizophrenia etiology. Ocular misalignment, or strabismus, falls into the category of MPAs, but this phenotype has not been assessed in schizophrenia. This study reveals that a subtype of strabismus, constant exotropia, displays marked association with schizophrenia (P=0.

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Article Synopsis
  • - Hypofunction of the NMDA receptor is linked to schizophrenia, as evidenced by substances like phencyclidine causing similar symptoms and mice lacking the NR2A subunit displaying abnormal behavior consistent with the disorder.
  • - The study focused on the GRIN2A gene, finding specific genetic variations that showed an association with schizophrenia, particularly a (GT)(n) repeat in its promoter region.
  • - Results revealed that longer versions of this repeat were more common in patients and correlated with more severe symptoms, indicating that these genetic variations may increase the risk and severity of schizophrenia by reducing GRIN2A levels in the brain.
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Dysregulation in dopaminergic neurotransmission might play a role in the pathogenesis of schizophrenia, and therefore genetic components of the dopamine (DA) pathway may confer risk. The NR4A2 (Nurr1) gene is essential for the development and maintenance of mesencephalic DA-synthesizing neurons. Moreover, Nurr1 forms a heterodimer with the retinoid X receptor and disturbances in the retinoid-signaling cascade may be involved in susceptibility to schizophrenia.

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