• Molecules and Cells
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• v.42 no.1
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• pp.28-35
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• 2019

Animals need to be able to alter their developmental and behavioral programs in response to changing environmental conditions. This developmental and behavioral plasticity is mainly mediated by changes in gene expression. The knowledge of the mechanisms by which environmental signals are transduced and integrated to modulate changes in sensory gene expression is limited. Exposure to ascaroside pheromone has been reported to alter the expression of a subset of putative G protein-coupled chemosensory receptor genes in the ASI chemosensory neurons of C. elegans (Kim et al., 2009; Nolan et al., 2002; Peckol et al., 1999). Here we show that ascaroside pheromone reversibly represses expression of the str-3 chemoreceptor gene in the ASI neurons. Repression of str-3 expression can be initiated only at the L1 stage, but expression is restored upon removal of ascarosides at any developmental stage. Pheromone receptors including SRBC-64/66 and SRG-36/37 are required for str-3 repression. Moreover, pheromone-mediated str-3 repression is mediated by FLP-18 neuropeptide signaling via the NPR-1 neuropeptide receptor. These results suggest that environmental signals regulate chemosensory gene expression together with internal neuropeptide signals which, in turn, modulate behavior.

• BMB Reports
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• v.54 no.6
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• pp.295-304
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• 2021

Olfactory neuropathology is a cause of olfactory loss in Alzheimer's disease (AD). Olfactory dysfunction is also associated with memory and cognitive dysfunction and is an incidental finding of AD dementia. Here we review neuropathological research on the olfactory system in AD, considering both structural and functional evidence. Experimental and clinical findings identify olfactory dysfunction as an early indicator of AD. In keeping with this, amyloid-β production and neuroinflammation are related to underlying causes of impaired olfaction. Notably, physiological features of the spatial map in the olfactory system suggest the evidence of ongoing neurodegeneration. Our aim in this review is to examine olfactory pathology findings essential to identifying mechanisms of olfactory dysfunction in the development of AD in hopes of supporting investigations leading towards revealing potential diagnostic methods and causes of early pathogenesis in the olfactory system.

• Physical Therapy Rehabilitation Science
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• v.11 no.3
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• pp.304-310
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• 2022

Objective: Mild cognitive impairment (MCI) is a condition in which cognitive and executive functions are reduced, and older adults with MCI are ten times more likely to develop dementia than healthy older adults. Expression of brain-derived neurotrophic factor (BDNF) through aerobic exercise is associated with increased cognitive and executive functions. in this review, randomized controlled trials (RCTs) on the effects of aerobic exercise on BDNF in individuals with mild cognitive impairment are summarized and qualitatively and quantitatively analyzed to suggest the necessity of aerobic exercise. Design: a systematic review and meta-analysis. Methods: RCTs were searched for changes in BDNF through aerobic exercise using four international databases. Quality assessment and quantitative analysis were performed using RevMan 5.4. Quantitative analysis was quantified with a standardized mean difference (SMD) and presented as a random effect model. Results: Three RCTs evaluated BDNF in 123 patients with MCI. There was a significant improvement in the experimental group that performed aerobic exercise compared to the control group. The results analyzed using the random effects model were SMD = 0.48. Conclusions: In this review, we reported the effects and mechanisms of aerobic exercise in individuals with MCI. As a result of synthesizing RCTs that performed aerobic exercise, a significant increase in BDNF was confirmed.

• The Korean Journal of Pain
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• v.35 no.3
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• pp.261-270
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• 2022

Background: The rostral ventromedial medulla (RVM) is a critical region for the management of nociception. The RVM is also involved in learning and memory processes due to its relationship with the hippocampus. The purpose of the present study was to investigate the molecular mechanisms behind orexin-A signaling in the RVM and hippocampus's effects on capsaicin-induced pulpal nociception and cognitive impairments in rats. Methods: Capsaicin (100 g) was applied intradentally to male Wistar rats to induce inflammatory pulpal nociception. Orexin-A and an orexin-1 receptor antagonist (SB-334867) were then microinjected into the RVM. Immunoblotting and immunofluorescence staining were used to check the levels of cyclooxygenase-2 (COX-2) and brain-derived neurotrophic factor (BDNF) in the RVM and hippocampus. Results: Interdental capsaicin treatment resulted in nociceptive responses as well as a reduction in spatial learning and memory. Additionally, it resulted in decreased BDNF and increased COX-2 expression levels. Orexin-A administration (50 pmol/1 µL/rat) could reverse such molecular changes. SB-334867 microinjection (80 nM/1 µL/rat) suppressed orexin's effects. Conclusions: Orexin-A signaling in the RVM and hippocampus modulates capsaicin-induced pulpal nociception in male rats by increasing BDNF expression and decreasing COX-2 expression.

• Korean Journal of Biological Psychiatry
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• v.30 no.1
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• pp.24-30
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• 2023

Objectives Alzheimer's disease (AD) is the most common form of dementia in older adults, damaging the brain and resulting in impaired memory, thinking, and behavior. The identification of differentially expressed genes and related pathways among affected brain regions can provide more information on the mechanisms of AD. The aim of our study was to identify differentially expressed genes associated with AD and combined biomarkers among them to improve AD risk prediction accuracy. Methods Machine learning methods were used to compare the performance of the identified combined biomarkers. In this study, three publicly available gene expression datasets from the hippocampal brain region were used. Results We detected 31 significant common genes from two different microarray datasets using the limma package. Some of them belonged to 11 biological pathways. Combined biomarkers were identified in two microarray datasets and were evaluated in a different dataset. The performance of the predictive models using the combined biomarkers was superior to those of models using a single gene. When two genes were combined, the most predictive gene set in the evaluation dataset was ATR and PRKCB when linear discriminant analysis was applied. Conclusions Combined biomarkers showed good performance in predicting the risk of AD. The constructed predictive nomogram using combined biomarkers could easily be used by clinicians to identify high-risk individuals so that more efficient trials could be designed to reduce the incidence of AD.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.4
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• pp.645-653
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• 2003

Taste receptor cells respond to gustatory stimuli using a complex arrangement of receptor molecules, signaling cascades and ion channels. When stimulated, these cells produce action potentials that result in the release of neurotransmitter onto an afferent nerve fiber that in turn relays the identity and intensity of the gustatory stimuli to tie brain. A variety of mechanisms are used in transducing the four primary tastes. Direct interaction of the stimuli with ion channels appears to be of particular importance in transducing stimuli reported as salty or sour, whereas tile second messenger systems cyclic AMP and inositol trisphosphate are important in transducing bitter and sweet stimuli. In addition to the four basic tastes, specific mechanisms exist for the amino acid glutamate, which is sometimes termed the fifth primary taste. The emerging picture is that not only do individual taste qualities use more than one mechanism, but multiple pathways are available for individual tastants as well.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.920-931
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• 2011

Nerve agents are irreversible inhibitors of the cholinesterase enzyme. Exposure causes a progression of toxic signs, including hypersecretions, fasciculations, tremor, convulsions, respiratory distress, epileptiform seizures, brain injuries and death. A combined regimen of prophylaxis and therapy is the most effective medical countermeasure for dealing with the threat of nerve agent poisoning to military personnel. In this paper, the author investigated the updated technologies regarding various pre- and post-treatment drugs for nerve agents detoxification which are under development in several countries including Korea. Some characteristics of active ingredients in the formulations of drugs, their action mechanisms, and effectiveness were analyzed. Additionally, part of experimental data on the transdermal patch studied in ADD using beagle dogs was introduced.

• Biomedical Science Letters
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• v.26 no.1
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• pp.1-7
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• 2020

Alzheimer's disease (AD) is the most common neurodegenerative disorder and is expected to become more and more widespread as life expectancy increases. New therapeutic target, as well as the identification of mechanisms responsible for pathology, is urgently needed. Recently, microglial actin cytoskeleton has been proposed as a beneficial role in axon regeneration of brain injury. This review highlights in understanding of the characteristics of microglial actin cytoskeleton and discuss the role of specific actin-interacting proteins and receptors in AD. The precise mechanisms and functional aspects of motility by microglia require further study, and the regulation of microglial actin cytoskeleton might be a potential therapeutic strategy for neurological diseases.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.303.1-303.1
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• 2002

Recent studies have suggested that the cerebral ischemia induced the neuronal cell death by mediating multiple mechanisms with necrosis and/or apoptosis. The present study examined neuroprotective mechanism of aloesin against transient focal cerebral ischemia. Aloesin. main component of aloe possesses various biological activates such as wound healing. anti-gastric ulcer. and chemopreventive activity. Transient focal cerebral ischemia was induced by 120 min MCAO. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.270.2-270.2
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• 2002

Dopamine D2 and D3 receptors (D2R and D3R) belong to pharmacological D2R family and share similar structural and functional characteristics. Elucidation of their differential functional characteristics is important for understanding their roles in brain. ERK1/2 was chosen as an example of signaling component of D2R and D3R and systemic studies were conducted to understand the regulatory mechanisms on ERK1/2 activation. (omitted)