• Title/Summary/Keyword: Physiological Functions

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Olfactory receptors in non-chemosensory tissues

  • Kang, NaNa;Koo, JaeHyung
    • BMB Reports
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    • v.45 no.11
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    • pp.612-622
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    • 2012
  • Olfactory receptors (ORs) detect volatile chemicals that lead to the initial perception of smell in the brain. The olfactory receptor (OR) is the first protein that recognizes odorants in the olfactory signal pathway and it is present in over 1,000 genes in mice. It is also the largest member of the G protein-coupled receptors (GPCRs). Most ORs are extensively expressed in the nasal olfactory epithelium where they perform the appropriate physiological functions that fit their location. However, recent whole-genome sequencing shows that ORs have been found outside of the olfactory system, suggesting that ORs may play an important role in the ectopic expression of non-chemosensory tissues. The ectopic expressions of ORs and their physiological functions have attracted more attention recently since MOR23 and testicular hOR17-4 have been found to be involved in skeletal muscle development, regeneration, and human sperm chemotaxis, respectively. When identifying additional expression profiles and functions of ORs in non-olfactory tissues, there are limitations posed by the small number of antibodies available for similar OR genes. This review presents the results of a research series that identifies ectopic expressions and functions of ORs in non-chemosensory tissues to provide insight into future research directions.

Melatonin inhibits nicotinic acetylcholine receptor functions in bovine chromaffin cells

  • Jo, Su-Hyun;Lee, Seung-Hyun;Kim, Kyong-Tai;Choi, Se-Young
    • International Journal of Oral Biology
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    • v.44 no.2
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    • pp.50-54
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    • 2019
  • Melatonin is a neurotransmitter that modulates various physiological phenomena including regulation and maintenance of the circadian rhythm. Nicotinic acetylcholine receptors (nAChRs) play an important role in oral functions including orofacial muscle contraction, salivary secretion, and tooth development. However, knowledge regarding physiological crosstalk between melatonin and nAChRs is limited. In the present study, the melatonin-mediated modulation of nAChR functions using bovine adrenal chromaffin cells, a representative model for the study of nAChRs, was investigated. Melatonin inhibited the nicotinic agonist dimethylphenylpiperazinium (DMPP) iodide-induced cytosolic free $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) increase and norepinephrine secretion in a concentration-dependent manner. The inhibitory effect of melatonin on the DMPP-induced $[Ca^{2+}]_i$ increase was observed when the melatonin treatment was performed simultaneously with DMPP. The results indicate that melatonin inhibits nAChR functions in both peripheral and central nervous systems.

Microbial 2-Cys Peroxiredoxins: Insights into Their Complex Physiological Roles

  • Toledano, Michel B.;Huang, Bo
    • Molecules and Cells
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    • v.39 no.1
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    • pp.31-39
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    • 2016
  • The peroxiredoxins (Prxs) constitute a very large and highly conserved family of thiol-based peroxidases that has been discovered only very recently. We consider here these enzymes through the angle of their discovery, and of some features of their molecular and physiological functions, focusing on complex phenotypes of the gene mutations of the 2-Cys Prxs subtype in yeast. As scavengers of the low levels of $H_2O_2$ and as $H_2O_2$ receptors and transducers, 2-Cys Prxs have been highly instrumental to understand the biological impact of $H_2O_2$, and in particular its signaling function. 2-Cys Prxs can also become potent chaperone holdases, and unveiling the in vivo relevance of this function, which is still not established, should further increase our knowledge of the biological impact and toxicity of $H_2O_2$. The diverse molecular functions of 2-Cys Prx explain the often-hard task of relating them to peroxiredoxin genes phenotypes, which underscores the pleiotropic physiological role of these enzymes and complex biologic impact of $H_2O_2$.

Effect of DIS Process on in vitro Physiological Functionality of Aloe vera Gel (알로에 겔의 in vitro 생리기능 특성에 미치는 삼투탈수공정의 영향)

  • Kim, Sung-A;Baek, Jin-Hong;Lee, Shin-Young
    • Food Engineering Progress
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    • v.13 no.4
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    • pp.251-261
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    • 2009
  • In vitro physiological functions such as jack bean (Canavalia ensiformis) urease inhibitory activity and retarding effect of glucose/bile acid of Aloe vera gel concentrated by the optimized DIS (Dewatering Impregnation & Soaking) process conditions were examined. Urease inhibitory activity of DIS aloes ranged from 84.6 to 94.4%, which was similar to or higher than 86.3% of fresh aloe. Also, urease inhibitory activity of DIS aloes was maintained at initial levels after heat treatment (90$^{\circ}C$, 10 min.) and drying treatment (freeze or hot air drying). Urease inhibition pattern from Lineweaver-Burk plot indicated general non-competitive inhibition, and inhibition constants ($K_{IE}$ and $K_{IES}$) of DIS aloes were 41-149 and 87-163 $\mu$L/mL, respectively. DIS(glucose) and DIS(polyethylene glycol) exhibited the highest retarding effect of glucose and bile acid. Their retarding effects were about 1.6 and 1.8 folds higher than that of fresh aloe after 0.5 and 1 hr of the dialysis, respectively. Conclusively, the above in vitro physiological functions of Aloe vera gel concentrated by DIS process suggested that aloe products treated with DIS would have the potential benefits for protection against Helicobacter pylori and reduction of blood glucose and cholesterol levels.

Association between the Brain-Derived Neurotropic Factor and Attention Deficit Hyperactivity Disorder (BDNF가 ADHD의 병인과 치료에 미치는 영향)

  • Kang, Na Ri;Song, Jae Min;Kwack, Young-Sook
    • Korean Journal of Biological Psychiatry
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    • v.25 no.2
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    • pp.21-30
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    • 2018
  • Attention deficit hyperactivity disorder (ADHD) is a common childhood psychiatric disorder. Recently, it has been suggested that brain-derived neurotropic factor (BDNF) may play a role in the pathogenesis of ADHD. Our aim of this review is to understand the physiological functions of BDNF and its potential relationship with ADHD and therapeutic approaches of ADHD. Searches were conducted in Pubmed and Research Information Service System (RISS). In this review, we summarized important literatures for the physiological functions of BDNF in neurodevelopment, change of serum BDNF level in ADHD, association of BDNF polymorphism and ADHD and potential association of treatment of ADHD with serum BDNF level. Further studies are required to more clearly understand the source and the role of BDNF in ADHD and to develop BDNF based-ADHD treatement.

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SAR of COX-2 Inhibitors (COX-2 억제제의 구조-활성)

  • 권순경
    • Biomolecules & Therapeutics
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    • v.9 no.2
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    • pp.69-78
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    • 2001
  • Cyclooxygenase (COX) is an enzyme, which catalyzes the production of prostaglandins from arachi-donic acid and exists in two isoforms (COX-1 and COX-2). COX-1 is involved in the maintenance of physiological functions such as platelet aggregation, cytoprotection in the stomach and maintenance of normal kidney function. COX-2 is induced significantly in vivo under inflammatory conditions. COX-1 and COX-2 serve different physiological and pathological functions. All commercially available nonsteroidal antiinflammatory drugs (NSAIDS) are inhibitors of both COX-1 and COX-2. Therefore, selective inhibitors of COX-2 may be effective antiinflammatory agents without the ulcerogenic effects associated with current NSAms. Since the mid 1990s, a number of reports have been appeared on the preparation and biological activity of selective COX-2 inhibitors. Recently celecoxib, and rofecoxib, the representative COX-2 inhibitors, are introduced in the drug market. In this paper the relationship of structure-activity for selective COX-2 inhibitors is reviewed.

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