• 제목/요약/키워드: inhibitory mechanism

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Benzo(a)pyrene의 돌연변이원성에 대한 유기게르마늄(GE-132)의 항돌연변이 효과 (Antimutagenic Effect of Organic Germanium(GE-132) on the Mutagenicity of Benzo(a)pyrene)

  • 이효민;정용;정기화;김재완;권순경
    • 약학회지
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    • 제37권1호
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    • pp.18-29
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    • 1993
  • This study was initiated to investigate the effective action and mechanism of GE-132 (Carboxyethylgermanium sesquioxide)on benzo(a)pyrene, which have strong carcinogenicity and mutagenicity. To confirm desmutagenic effect (inhibition of metabolic processes of benzo(a)pyrene with S9 Mix or inactivation of the mutagenicity of benzo(a)pyrene metabolites) and antimutagenic effect (inhibition of gene-expression of reverted genes) of GE-132 against benzo(a)pyrene using with Salmonella typhimuyium TA98 Ames test was performed. The revertants in desmutagenicity test were decreased significantly in the combined groups of benzo(a)pyrene and GE-132 than benzo(a)pyrene only, without inhibition the metabolism of benzo(a)pyrene by S9 Mix. The ideal combined groups of benzo(a)pyrene and GE-132 were 10 $\mu{M}$ and 10mg, 20 $\mu{M}$ and 20mg, 100 $\mu{M}$ and 30 mg, respectively. Then, the revertants in antimutagenicity test, which was studied the direct action of GE-132 on the induction of revertant cells by Salmonella typhimurium TA98 and activated benzo(a)pyrene were decreased significantly in the treated groups of GE-132 than no treated groups. The number of revertants of Salmonella typhimurium TA98 were reduced with increasing amounts of GE-132. From the above results, it was found that GE-132 inactivated the mutagenic metabolites of benzo(a)pyrene without inhibition of the enzyme action in the S9 Mix, and GE132 showed antimutagenic effect which have inhibitory action of reverted gene expression.

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홍화자, 향부자, 형개 추출물의 미백효과에 관한 연구 (A Study on the Depigmenting Effect of Carthamus tinctorius Seed, Cyperus rotundus and Schizonepeta tenuifolia Extracts)

  • 황은영;김동희;황주영;김희정;박태순;이인선;손준호
    • 한국식품과학회지
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    • 제44권1호
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    • pp.76-81
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    • 2012
  • 본 연구에서는 3가지 홍화자, 향부자, 형개 추출물의 미백효과를 연구하였다. 멜라닌 생성 첫 단계인 tyrosinase 억제활성과 멜라닌 생성 억제효과를 측정한 결과, 홍화자 에탄올 추출물이 tyrosinase 활성과 B16F10 melanoma 세포의 멜라닌 생성 억제하였다. 그 결과, 홍화자 추출물은 B16F10 melanoma 세포에서 melanogenesis 따른 tyrosinase 형성 억제에 따른 멜라닌 합성 관련 인자 MITF, tyrosinase, TRP-1, TRP-2 의 발현을 억제함에 따라 홍화자 추출물의 미백효과를 확인하였다. 따라서 홍화자는 미백효과를 가진 천연 기능성 재료로서 가능성이 매우 높은 것으로 판단된다.

마황천오 약침액이 3T3-L1 지방세포 분화 및 유전자발현에 미치는 영향 (Effects of Mahuang-Chuanwu(Mahwang-Cheonoh) Pharmacopuncture Solution on Adipocyte Differentiation and Gene Expression in 3T3-L1 Adipocytes)

  • 강경화
    • Korean Journal of Acupuncture
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    • 제31권4호
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    • pp.168-178
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    • 2014
  • Objectives : Mahuang-Chuanwu(Mahwang-Cheonoh) Pharmacopuncture(MCP) has been used to treat obesity in Clinical Korean Medicine. MCP solution(MCPS) is also expected to have strong anti-obesity activities. However, little is known about the mechanisms of its inhibitory effects on adipocyte differentiation and lipogenesis. Methods : In the present study, we examined the effects of MCPS on differentiation and lipogenesis of 3T3-L1 adipocytes. To elucidate the mechanism of the effects of MCPS on lowering lipid content in 3T3-L1 adipocytes, we examined whether MCPS modulates the expressions of transcription factors to induce lipogenesis and adipogenic genes related to regulate the accumulation of lipids. Results : Our results showed that MCPS significantly inhibited differentiation and lipogenesis of 3T3-L1 adipocytes in a dose-dependent manner. MCPS suppressed the mRNA expressions of cytidine-cytidine-adenosine-adenosine-thymidine(CCAAT)/enhancer binding proteins ${\alpha}$($C/EBP{\alpha}$), C/EBP ${\beta}$, $C/EBP{\delta}$, and peroxisome proliferator-activated receptor ${\gamma}$($PPAR{\gamma}$) genes related to the induction of adipose differentiation. MCPS inhibited the mRNA expressions of adipose-specific aP2, adipsin, lipoprotein lipase(LPL), CD36, TGF-${\beta}$, and leptin genes related to the fat formation. MCPS downregulated the mRNA expressions of liver X receptor(LXR) ${\alpha}$ and fatty acid synthase(FAS) genes related to the induction of lipogenesis. In addition, MCPS reduced the production of adipocyte-induced pro-inflammatory cytokines. Conclusions : MCPS could regulate the accumulation of lipids and expression of adipogenic genes via inhibition of transcript factors related to induction of adipose differentiation.

Oxymatrine Causes Hepatotoxicity by Promoting the Phosphorylation of JNK and Induction of Endoplasmic Reticulum Stress Mediated by ROS in LO2 Cells

  • Gu, Li-li;Shen, Zhe-lun;Li, Yang-Lei;Bao, Yi-Qi;Lu, Hong
    • Molecules and Cells
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    • 제41권5호
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    • pp.401-412
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    • 2018
  • Oxymatrine (OMT) often used in treatment for chronic hepatitis B virus infection in clinic. However, OMT-induced liver injury has been reported. In this study, we aim to investigate the possible mechanism of OMT-induced hepatotoxicity in human normal liver cells (L02). Exposed cells to OMT, the cell viability was decreased and apoptosis rate increased, the intracellular markers of oxidative stress were changed. Simultaneously, OMT altered apoptotic related proteins levels, including Bcl-2, Bax and pro-caspase-8/-9/-3. In addition, OMT enhanced the protein levels of endoplasmic reticulum (ER) stress makers (GRP78/Bip, CHOP, and cleaved-Caspase-4) and phosphorylation of c-Jun N-terminal kinase (p-JNK), as well as the mRNA levels of GRP78/Bip, CHOP, caspase-4, and ER stress sensors (IREI, ATF6, and PERK). Pre-treatment with Z-VAD-fmk, JNK inhibitor SP600125 and N-acetyl-l-cysteine (NAC), a ROS scavenger, partly improved the survival rates and restored OMT-induced cellular damage, and reduced caspase-3 cleavage. SP600125 or NAC reduced OMT-induced p-JNK and NAC significantly lowered caspase-4. Furthermore, 4-PBA, the ER stress inhibitor, weakened inhibitory effect of OMT on cells, on the contrary, TM worsen. 4-PBA also reduced the levels of p-JNK and cleaved-caspase-3 proteins. Therefore, OMT-induced injury in L02 cells was related to ROS mediated p-JNK and ER stress induction. Antioxidant, by inhibition of p-JNK or ER stress, may be a feasible method to alleviate OMT-induced liver injury.

STAT3 활성 억제를 유도하는 resveratrol의 호르몬 불응성 전립선 암 예방 효과 (Resveratrol Prevents Hormone-refractory Prostate Cancer Cell Growth via Inhibition of STAT3 Activity)

  • 조석철;최부영
    • 한국식품과학회지
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    • 제46권4호
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    • pp.516-521
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    • 2014
  • 전립선암은 발병률이 높은 암종 중에 하나이다. 전립선 치료제인 flutamide는 androgen 수용체의 호르몬 치료제로서 내성효과에 대한 기본 메커니즘은 명확하지 않다. 본 연구에서는 flutamide에 의해 유도되는 호르몬 불응성 전립선 암세포 성장에서 포도 성분인 resveratrol의 억제효과를 조사하였다. 본 연구의 결과를 통해 호르몬 비의존적인 신호전달의 전환으로 유발되는 호르몬 불응성 전립선 암에서 resveratrol은 예방 및 항암효과에 기여할 것이라 판단된다.

RV-23, a Melittin-Related Peptide with Cell-Selective Antibacterial Activity and High Hemocompatibility

  • Zhang, Shi-Kun;Ma, Qian;Li, Su-Bo;Gao, Hong-Wei;Tan, Ying-Xia;Gong, Feng;Ji, Shou-Ping
    • Journal of Microbiology and Biotechnology
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    • 제26권6호
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    • pp.1046-1056
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    • 2016
  • RV-23 is a melittin-related antibacterial peptide (MRP) with lower cytotoxicity than either melittin or AR-23, another MRP. The aim of this study was to explore the mechanism of RV-23's antibacterial selectivity and its hemocompatibility. The results showed that all the peptides exhibited lytic activity against Staphylococcus aureus and Escherichia coli, with RV-23 showing the highest potency. Moreover, RV-23 had lower cytotoxicity than melittin or AR-23 at their minimal inhibitory concentration. In addition, CD experiments showed that melittin, RV-23, and AR-23 all had a typical α-helical structure, and RV-23 had the lowest α-helix content. The structural information showed that RV-23 has the lowest hydrophobicity and highest hydrophobic moment. Because hydrophobicity and α-helix content are believed to correlate with hemolysis, the results indicate that the selective lytic activity against bacteria of RV-23 may be due to its low hydrophobicity and α-helicity, which lead to low cytotoxicity without affecting antibacterial activity. Furthermore, RV-23 did not affect the structure and function of blood components such as red blood cells, platelets, albumin, and the blood coagulation system. In conclusion, RV-23 is a cell-selective antibacterial peptide with high hemocompatibility due to its unique structure.

Effects of Prostaglandin $E_2$ on the Spontaneous Contractions and Electrical Activities of the Antral Circular Muscle in Guinea-pig Stomach

  • Kim, Jong-Yoon;Kim, Sung-Joon;Kang, Tong-Mook;Lee, Sang-Jin;Jun, Jae-Yeoul;So, In-Suk;Kim, Ki-Whan
    • The Korean Journal of Physiology and Pharmacology
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    • 제2권3호
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    • pp.361-368
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    • 1998
  • The spontaneous contractions of gastric smooth muscles are regulated by slow waves, which are modulated by both nervous system and humoral agents. This study was designed to examine the effects of prostaglandin $E_2$ ($PGE_2$) on the contractile and electrical activities of antral smooth muscles in guinea-pig stomach, using an intracellular recording technique. To elucidate the underlying mechanism for its effect on contractility, ionic currents were also measured using a whole-cell patch clamp method. The basal tone by $PGE_2$ was variable, whereas the magnitude of phasic contractions was reduced ($19.0{\pm}2.1%$, n=19). The resting membrane potentials were hyperpolarized ($-4.4{\pm}0.5%$ mV, n=10), and plateau potentials were lowered ($-2.9{\pm}0.5%$ mV, n=10). In most cases, however, the initial peak potentials of slow waves were depolarized more by $PGE_2$ than those of control. The frequency of the slows wave was increased from $5.7{\pm}0.2$ cycles/min to $6.5{\pm}0.2$ (n=22). Voltage-operated $Ca^{2+}$ currents were decreased by $PGE_2$ (n=5). Voltage-operated $K^+$ currents, both Ca-dependent and Ca-independent, were increased (n=5). These results suggest that $PGE_2$ plays an important role in the modulation of gastric smooth muscle activities, and its inhibitory effects on the contractility and activities of slow waves are resulted from both decrease of $Ca^{2+}$ currents and increase of $K^+$ currents.

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Intracisternal Antidepressants Suppressed the Nociceptive Jaw Opening Reflex in Freely Moving Rats

  • Ahn, Dong-Kuk;Kim, Yun-Sook
    • The Korean Journal of Physiology and Pharmacology
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    • 제2권3호
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    • pp.307-312
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    • 1998
  • This study was performed to investigate the mechanism of central analgesic effects of antidepressants. Thirty four male rats were anesthetized with pentobarbital sodium (40 mg/kg, ip). A stainless steel guide cannula and a PE tube (PE10) were implanted into the lateral ventricle and cisterna magna area. Stimulating and recording electrodes were implanted into the incisor pulp and anterior digastric muscle. Electrodes were led subcutaneously to the miniature cranial connector sealed on the top of the skull with acrylic resin. The jaw opening reflex was used in freely moving rats, and antidepressants were administered intracisternally in order to eliminate the effects of anesthetic agents on the pain assessment and evaluate the importance of the central action site of antidepressants. After 48 hours of recovery from surgery, digastric electromyogram (dEMG) of freely moving rats was recorded. Electrical shocks (200 ${\mu}sec$ duration, 0.5-2 mA intensity) were delivered at 0.5 Hz to the dental pulp every 2 minute. Intracisternal administration of $15\;{\mu}g$ imipramine suppressed dEMG elicited by noxious electrical stimulation in the tooth pulp to $76{\pm}6%$ control. Intracisternal administration of $30\;{\mu}g$ desipramine, nortriptyline, or imipramine suppressed dEMG remarkably to $48{\pm}2,\;27{\pm}8,\;or\;25{\pm}5%$ of the control, respectively. Naloxone, methysergide, and phentolamine blocked the suppression of dEMG produced by intracisternal antidepressants from $23{\pm}2\;to\;69{\pm}4%,\;from\;32{\pm}5\;to\;80{\pm}9%,\;and\;from\;24{\pm}6\;to\;77{\pm}5%$ of the control, respectively. These results indicate that antidepressants produce antinociception through central mechanisms in the orofacial area. Antinociception of intracisternal antidepressants seems to be mediated by an augmentation of descending pain inhibitory influences on nociceptive pathways.

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Roles of Non-cholinergic Intrapancreatic Nerves, Serotonergic Nerves, on Pancreatic Exocrine Secretion in the Isolated Perfused Rat Pancreas

  • Jiang, Zheng Er;Shin, Bich-Na;Kim, In-Hye;Lee, Hyun-Joo;Yong, Jun-Hwan;Lee, Min-Jae;Won, Moo-Ho;Lee, Yun-Lyul
    • The Korean Journal of Physiology and Pharmacology
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    • 제15권5호
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    • pp.307-312
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    • 2011
  • It has been rereported that axons which display 5-hydroxytryptamine (5-HT) immunoreactivity are abundant in the pancreas and the majority of serotonergic axons terminate within intrapancreatic ganglia, islet and acini. This histological result strongly suggests that intrapancreatic serotonergic nerves could affect to the pancreatic endocrine and exocrine secretion. Thus, this study was aimed to investigate whether intrapancreatic serotonergic nerves could affect pancreatic exocrine secretion and an action mechanism of the intrapancreatic serotonergic nerves. The rats were anesthetized with a single injection of urethane. The median line and the abdominal aorta was carefully dissected and cannulated with PE-50 tubing just above the celiac artery, and then tightly ligated just below the superior mesenteric artery. The pancreatic duct was also cannulated with Tygon microbore tubing. With the addition of serotonin, pancreatic volume flow and amylase output were significantly inhibited electrical field stimulation (EFS). On the other hand, pancreatic volume flow and amylase output were significantly elevated in EFS with the addition of spiperone. EFS application, however, pancreatic volume flow and amylase output had no significant change in cholecystokinin (CCK) alone when serotonin was applied under a 5.6 mM glucose background. Pancreatic volume flow and amylase output under 18 mM glucose background were significantly elevated in CCK plus serotonin than in CCK alone. These data suggest that intrapancreatic serotonergic nerves play an inhibitory role in pancreatic exocrine secretion and an important role in the insulin action or release.

Glycine- and GABA-mimetic Actions of Shilajit on the Substantia Gelatinosa Neurons of the Trigeminal Subnucleus Caudalis in Mice

  • Yin, Hua;Yang, Eun-Ju;Park, Soo-Joung;Han, Seong-Kyu
    • The Korean Journal of Physiology and Pharmacology
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    • 제15권5호
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    • pp.285-289
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    • 2011
  • Shilajit, a medicine herb commonly used in Ayurveda, has been reported to contain at least 85 minerals in ionic form that act on a variety of chemical, biological, and physical stressors. The substantia gelatinosa (SG) neurons of the trigeminal subnucleus caudalis (Vc) are involved in orofacial nociceptive processing. Shilajit has been reported to be an injury and muscular pain reliever but there have been few functional studies of the effect of Shilajit on the SG neurons of the Vc. Therefore, whole cell and gramicidin-perfotrated patch clamp studies were performed to examine the action mechanism of Shilajit on the SG neurons of Vc from mouse brainstem slices. In the whole cell patch clamp mode, Shilajit induced short-lived and repeatable inward currents under the condition of a high chloride pipette solution on all the SG neurons tested. The Shilajit-induced inward currents were concentration dependent and maintained in the presence of tetrodotoxin (TTX), a voltage gated $Na^+$ channel blocker, CNQX, a non-NMDA glutamate receptor antagonist, and AP5, an NMDA receptor antagonist. The Shilajit-induced responses were partially suppressed by picrotoxin, a $GABA_A$ receptor antagonist, and totally blocked in the presence of strychnine, a glycine receptor antagonist, however not affected by mecamylamine hydrochloride (MCH), a nicotinic acetylcholine receptor antagonist. Under the potassium gluconate pipette solution at holding potential 0 mV, Shilajit induced repeatable outward current. These results show that Shilajit has inhibitory effects on the SG neurons of Vc through chloride ion channels by activation of the glycine receptor and $GABA_A$ receptor, indicating that Shilajit contains sedating ingredients for the central nervous system. These results also suggest that Shilajit may be a potential target for modulating orofacial pain processing.