Publications by authors named "Koichi Isogawa"

Objectives: The underlying pathogenic mechanisms and predictors of recurrence in major depressive disorder are still largely unknown. Hypothalamic-pituitary-thyroid (HPT) axis and hypothalamus-pituitary-adrenocortical (HPA) axis dysregulation are thought to be related to the development and course of depression.

Design And Setting: Over a ten-year period, we investigated whether the results of thyrotropin-releasing hormone (TRH) testing and combined dexamethasone/corticotropin-releasing hormone (DEX/CRH) testing could be correlated with the recurrence of depression in 25 outpatients with clinically remitted major depression for at least 10 years.

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Background: The lateral nucleus of the amygdala (LA) is a crucial part of the neural circuitry underlying the formation and storage of memories established through fear conditioning. To investigate corticotropin-releasing factor (CRF) contributions to fear memory in LA, the present experiments tested the effects of intra-LA infusions on the formation and expression of memory after Pavlovian fear conditioning.

Methods: In experiment 1, CRF was infused bilaterally into LA of rats 1 hour before fear conditioning training.

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  • * Forty-five patients over 50 years old with moderate MDD were treated for 8 weeks, with 12 showing positive responses and 33 not responding to SSRIs; a comparison group of 30 healthy individuals was also included.
  • * Results indicated that non-responsive patients had lower brain blood flow in certain areas compared to responders and controls, suggesting that low blood flow in the frontal cortex may be an indicator of poor SSRI response in older adults.
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  • Two models exist regarding ghrelin's role in stress responses: it may either contribute to stress-induced depression and anxiety or help alleviate these symptoms.
  • A study measured serum ghrelin levels and mood/anxiety scores in individuals with major depressive disorder (MDD) and panic disorder, comparing treatment-resistant patients to responders and healthy controls.
  • Findings showed higher ghrelin levels in treatment-resistant patients, suggesting that lower ghrelin levels may enhance the effect of antidepressant treatments in MDD and panic disorder.
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  • - Major depressive disorder (MDD) and panic disorder (PD) have both stress and genetic factors contributing to their development, linked to the hypothalamic-pituitary-adrenal (HPA) axis and specific receptors like CRHR1 and CRHR2.
  • - A study identified specific single nucleotide polymorphisms (SNPs) in these receptors that are associated with MDD and PD, investigating a total of 178 MDD patients, 180 PD patients, and 285 healthy controls.
  • - Notable findings included associations of certain SNPs (like rs110402, rs242924, and rs3779250) and haplotypes in CRHR1 with MDD, and CRHR1 SNPs also
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Psychosocial stress-induced activation of salivary α-amylase (sAA) functions is as a marker of sympathoadrenal medullary system (SAM) activity. However, in contrast to salivary cortisol, sAA has been less extensively studied in panic disorder patients. The present study measured sAA and salivary cortisol levels in patients with panic disorder following electrical stimulation stress.

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  • The main treatment for obsessive-compulsive disorder (OCD) is selective serotonin reuptake inhibitors (SSRIs), but about one-third of patients don’t respond to them and continue to struggle with symptoms.
  • Researchers added aripiprazole to SSRI treatment for 13 patients who previously did not respond to SSRIs, administering the combination for at least 7 weeks.
  • The results showed significant improvement in OCD symptoms, but many patients also experienced side effects, needing additional medications to manage these issues.
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The G protein-coupled receptor 39-b (GPR39-1b) is a splice variant of which is expressed in the central nervous and gastrointestinal systems. Previously, GPR39-1b was proposed to be the receptor for obestatin, but current evidence does not support this hypothesis. The purpose of the present work was to identify the role of GPR39-1b in anxiety and eating behaviors.

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Major depressive disorder (MDD) is often associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis by chronic stress. In comparison, psychosocial stress-induced activation of salivary α-amylase (sAA) functions as a marker of sympathoadrenal medullary system (SAM) activity. However, in contrast to salivary cortisol, sAA has been less extensively studied in MDD patients.

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  • Bright light therapy, particularly infrared radiation, has been researched for its potential to alleviate symptoms of depression and anxiety in humans.
  • In an animal study, rats were divided into groups receiving either acute or chronic exposure to infrared radiation, or a control group that was not exposed but received a placebo treatment.
  • Results showed that chronic exposure to infrared radiation significantly reduced signs of depression and anxiety in the rats, suggesting potential therapeutic benefits similar to those seen with bright light therapy in humans.
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Abstract Objective. Major depressive disorder (MDD) is often associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis via chronic stress. Psychosocial stress-induced activation of salivary α-amylase (sAA) represents sympathoadrenal medullary system (SAM) activity, and sAA has become an emerging biomarker for sympathetic nervous system activity.

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The results of the thyrotropin-releasing hormone (TRH) stimulation test and the combined dexamethasone/corticotropin-releasing hormone (DEX/CRH) test are believed to correlate with social support status in patients with major depressive disorder. We studied 41 consecutive patients hospitalized for major depressive disorder and tested their responses to DEX/CRH and TRH on hospital days 4-7. DeltaMAX TSH and DeltaMAX cortisol were measured.

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Hepatocyte growth factor (HGF) is induced in neurons during ischemia and is neuroprotective against post-ischemic delayed neuronal death in the hippocampus. HGF might play an important role in the maturation and functioning of these neurons in the hippocampus. Our aim was to determine what effect HGF antisense has on depression and anxiety in rats.

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Background: It is commonly believed that there exists a relationship between the outcome of thyrotropin-releasing hormone (TRH) test, the combined dexamethasone/corticotropin-releasing hormone (DEX/CRH) test and stressful life events (SLEs) in major depressive disorder.

Objective: SLEs influence the TRH and DEX/CRH tests in major depressive disorder when administered at the time of admission and improvement.

Methods: The TRH and DEX/CRH tests were administered to patients hospitalized for major depressive disorders - on the 4th through the 7th hospital day and at the time of improvement.

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We reviewed recent knowledge and a biologic base of anxiety disorders. As for brain image study, mainly study on PET, fMRI and NIRS has advanced. The neural circuit hypothesis of Gorman still attracts attention.

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Rationale: Ghrelin is a peptide of 28 amino acids found in mammals that increases the release of growth hormone, food intake, and body weight.

Objectives: We investigated the relationship between ghrelin and the states of anxiety and depression by giving rats either antisense DNA for ghrelin, scrambled DNA or vehicle into the lateral ventricle of rats.

Results: In forced swimming tests, rats that received antisense DNA decreased the length of time that they were immobile in the water.

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The aim of this study was to investigate methods for predicting the efficacy of electroconvulsive therapy (ECT) in patients with major depressive disorder. Subjects comprised 24 inpatients with major depressive disorder diagnosed according to DSM-IV criteria who were resistant to antidepressant therapy or who, due to adverse reactions, could not undergo pharmacotherapy at adequate doses for sufficient durations. ECT was generally performed 12 times using a sinusoidal-wave device.

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There is compelling evidence for the involvement of hypothalamic-pituitary-adrenal (HPA) axis abnormalities in depression. Growing evidence has suggested that the combined dexamethasone (DEX)/corticotropin-releasing hormone (CRH) test is highly sensitive to detect HPA axis abnormalities. We organized a multicenter study to assess the DEX/CRH test as a state-dependent marker for major depressive episode in the Japanese population.

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We performed a prospective study designed to examine whether or not evaluation of the severity and prediction of treatment outcome in major depressive disorder would be enabled by simultaneous use of the thyrotropin-releasing hormone (TRH) test and the combined dexamethasone/corticotropin-releasing hormone (DEX/CRH) test. We studied consecutive patients hospitalized for major depressive disorder. The patients received the TRH test and the DEX/CRH test on the 4th through the 7th hospital days and at the time of improvement.

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Repetitive transcranial magnetic stimulation (rTMS) is effective for treatment of several psychiatric disorders such as depression and anxiety disorder. However, some reports suggest that rTMS induced anxiety in normal volunteers. Consistent with this observation, we have reported that chronic rTMS induces anxiety in normal rats which was suppressed by chronic treatment, but not acute paroxetine treatment.

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Background: Hepatocyte growth factor (HGF) has the capacity to selectively direct thalamocortical projections into an intermediate target, the pallidum, and eventually to their final cortical destination. HGF may have a role in the mediation of anxiety. Very little is known about other central behavioral effects of HGF.

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Cholecystokinin 2 (CCK2) receptors have been implicated as mediators of anxiety in standard mouse models such as exploratory behavior both in black and white test boxes and in elevated plus-mazes. We investigated the role of the CCK2 receptor in anxiety by evaluating the behavior of mice lacking the gene for this receptor in these standard anxiety models (i.e.

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