• The Korean Journal of Physiology and Pharmacology
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• 제13권6호
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• pp.461-467
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• 2009

The auditory cortex (A1) encodes the acquired significance of sound for the perception and interpretation of sound. Nitric oxide (NO) is a gas molecule with free radical properties that functions as a transmitter molecule and can alter neural activity without direct synaptic connections. We used whole-cell recordings under voltage clamp to investigate the effect of NO on spontaneous GABAergic synaptic transmission in mechanically isolated rat auditory cortical neurons preserving functional presynaptic nerve terminals. GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) in the A1 were completely blocked by bicuculline. The NO donor, S-nitroso-N-acetylpenicillamine (SNAP), reduced the GABAergic sIPSC frequency without affecting the mean current amplitude. The SNAP-induced inhibition of sIPSC frequency was mimicked by 8-bromoguanosine cyclic 3',5'-monophosphate, a membrane permeable cyclic-GMP analogue, and blocked by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a specific NO scavenger. Blockade of presynaptic $K^+$ channels by 4-aminopyridine, a $K^+$ channel blocker, increased the frequencies of GABAergic sIPSCs, but did not affect the inhibitory effects of SNAP. However, blocking of presynaptic $Ca^{2+}$ channels by $Cd^{2+}$, a general voltage-dependent $Ca^{2+}$ channel blocker, decreased the frequencies of GABAergic sIPSCs, and blocked SNAP-induced reduction of sIPSC frequency. These findings suggest that NO inhibits spontaneous GABA release by activation of cGMP-dependent signaling and inhibition of presynaptic $Ca^{2+}$ channels in the presynaptic nerve terminals of A1 neurons.

• Nuclear Engineering and Technology
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• 제48권3호
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• pp.608-612
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• 2016

D-(+)-glucose (Glc) was added to the original Fricke polyvinyl alcohol-glutaraldehyde-xylenol orange (FPGX) hydrogel dosimeter system to make a more stable FPGX hydrogel three-dimensional dosimeter in this paper. Polyvinyl alcohol was used as a substrate, which was combined with Fricke solution. Various concentrations of Glc were tested with linear relevant fitting for optimal hydrogel production conditions. The effects of various formulations on the stability and sensitivity of dosimeters were evaluated. The results indicated that D-(+)-Glc, as a free radical scavenger, had a great effect on stabilizing the dose response related to absorbency and reducing the auto-oxidization of ferrous ions. A careful doping with Glc could slow down the color change of the dosimeter before and after radiation without any effect on the sensitivity of the dosimeter.

• 대한한의학회지
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• 제17권1호
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• pp.465-477
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• 1996

Inhibitory effects of Hyeulbuchuckeutang(H.B.T) On the peroxidations of lecithin-liposomes by active oxygens, hydroxyl radical and superoxide anion, derived from hydrogen $peroxidase-Fe^{2+}$ system and xanthine- xanthine oxidase system. These effects were similar to and stronger than those of catalase, mannitol, superoxide dismutase or $dl-{\alpha}-tocopherol$ as a scavenger or an antioxidant. H.B.T. inhibited the peroxidation of lecithin-liposome and active oxygens in concentration-dependent manner. H.B.T. also dose-dependently protected the cell death mduced by tert-butvlhydroperoxide(tBHP) and significantly increased cell viability in the rat normal liver cell (Ac2F). These results suggested that H.B.T might playa protective role in lipid peroxidation by free radicals and tBHP.

• 약학회지
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• 제47권4호
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• pp.224-229
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• 2003

We have investigated the transport characteristics of synthetic antioxidant and free radical scavenger, $\alpha$-phenyl-n-tert-butyl nitrone (PBN) at the blood-brain barrier (BBB) by in vitro uptake study in conditionally immortalized rat brain capillary endothelial cell line (TR-BBB). Also, the efflux of PBN from brain to blood is estimated using the brain efflux index (BEI) method. Choline is a charged organic cation, including nitrogen-methyl group and shows the carrier-mediated distribution to the brain. [$^3$H]Choline uptake by TR-BBB cells was significantly inhibited by PBN with $IC_{50}$/ of 1.2 mM, which appears to be due to similar structures between choline and PBN. And, PBN was microinjected into Par2 of the rat brain by BEI method, and was eliminated from the brain with an apparent elimination half-life of about 2 min. Also, [$^3$H]choline efflux was significantly inhibited by PBN using BEI method. In conclusion, the efflux transport of PBN takes place across the BBB and PBN may be transported into the brain and eliminated from the brain by BBB choline transporter.

• 농업과학연구
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• 제44권3호
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• pp.309-317
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• 2017

Melatonin (N-acetyl-5-methoxytryptamine) is an indole synthesized from tryptophan by the pineal gland in animal. The major function of melatonin is to modulate circadian and circannual rhythms in photoperiodic mammals. Importantly, however, melatonin is also a free radical scavenger, anti-oxidant, and anti-apoptotic agent. Recently, the beneficial effects of melatonin on oocyte maturation and embryonic development in vitro have been reported in many species such as pig, cattle, sheep, mouse, and human. In this review, we will discuss recent studies about the role of melatonin in the production of porcine and bovine oocytes and embryos in vitro in order to provide useful information of melatonin in oocyte maturation and embryo culture in vitro.

• Journal of Radiation Protection and Research
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• 제26권4호
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• pp.347-356
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• 2001

Guarana, a tropical plant is found in powdered for in health food and is very popular soft drink in Brazil as an energy feaster with its high caffeine contents. We examined its radioprotection effects during organogenesis stages of ICR mice by malformations rate and cellular lead 8 the embryo by radiation and analyzed the mechanism of the radioprotection effects in the fetal of ICR mice. The results of this study showed that Guarana reduced clearly the embryonic death rate and teratogenesis rate by radiation. Its radioprotection effect inject be related with its radioprotection effect might be related with its antioxidant effect or free radical scavenger. We need to exposure the Guarana as a potential radioprotection agent. Therefore, we investigated about radiation effects by Guarana using to mice experiments in this paper.

• 한국환경보건학회지
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• 제22권4호
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• pp.102-108
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• 1996

Inhibitory effects of tannic acid on the lipid peroxidation induced by UVB were investigated. Tannic acid was administered either topically or orally for 3 days to hairless mice, which were previously irradiated with UVB, and inhibitory effects of tannic acid were measured. The UVB was found to cause skin erythema and hemolysis. When tannic acid was administered either topically or orally, hemolysis was decreased. After the skin was irradiated by UVB, the production of malondialdehyde was significantly decreased in erythrocyte and skin tissue, and the activities of SOD and catalase were significantly increased in plasma and skin tissue. In case of oral treatment, catalase activity was not significantly increased. The inhibitory effects of tannic acid on malondialdehyde production, SOD inhibition and catalase inhibition were more prominent in orally administerd groups than in topically administerri groups. However, the difference between two groups was not statistically significant. In conclusion, tannic acid decreased lipid peroxidation possibly by free radical scavenger action. The route of administrations, topical or oral, did not affect the antioxidative activity of tannic acid.

• 한국작물학회지
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• 제52권4호
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• pp.447-452
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• 2007

괴경 내부에 적색과 보라색 안토시아닌 색소가 풍부하게 함유되어 있고, 색상의 기호도 및 건강 기능성으로 인해 소비자로부터 기호도가 증대된 유색감자의 생리적 활성을 검토하기 위해 유색감자의 대조구로 괴경 내부가 백색인 수미 품종을 사용하고, 유색감자로서 괴경 내부가 적색인 대관 1-102호, 괴경 내부가 보라색인 자심품종과 대관 1-104호로 구분하여 항산화, 활성산소 소거능 및 항고혈압 활성을 비교, 검토한 결과는 아래와 같다. 1. 유색감자 추출물의 항산화 활성 검정결과 추출물의 농도가 $10{\mu}g/mL$ 수준에서는 유색감자별 차이를 나타내지 않았으나, $50{\mu}g/mL$을 처리한 경우 시료 간 차이를 뚜렷하게 나타내었으며, 유색감자 중 괴경내부의 색상이 적색인 대관 1-102호가 34%의 높은 저해율을 나타내어 30%의 저해율을 나타낸 활성평가 대조구인 $\alpha-tocopherol$보다 높은 항산화 활성을 나타내었다. 2. 유색감자 추출물의 자유 라디칼 소거 활성에서는 괴경 내부가 보라색인 대관 1-104호가 50%의 소거능을 나타내는 농도가 $9.83{\mu}g/mL$로 가장 높은 라디칼 소거활성을 나타내었으며, 이 결과 또한 대조시약인 $\alpha-tocopherol$이나 BHT보다 높은 소거 활성을 나타내었다. 3. 유색감자 추출물의 xanthine oxidase 활성 억제효과를 검토한 결과 유색감자 간에 큰 차이를 나타내어 대관 1-102호와 1-104호의 경우 xanthine oxidase 활성을 50% 저해하는 데 필요한 농도는 약 $26{\mu}g/mL$ 수준으로 가장 높게 조사되었으며, 다음으로 수미($46{\mu}g/mL$), 자심($49{\mu}g/mL$)의 순으로 조사되었다. 4. 유색감자 추출물의 ACE 저해 활성을 검토한 결과 항고혈압 대조구 활성물질인 captopril의 수준에는 미치지 못하나 유색감자 간에는 명확한 차이를 나타내었다. 괴경내부색상이 적색인 대관 1-102호가 $117.7{\mu}g/mL$으로 가장 높은 ACE 저해 활성을 나타내었으며, 내부색상이 보라색인 대관 1-104호와 자심은 $130{\mu}g/mL$로 유사한 양상을 나타내었으며, 괴경내부 색상이 백색을 나타내는 수미품종은 $192{\mu}g/mL$으로 가장 낮은 활성을 나타내었다. 5. 이상의 결과를 종합해 볼 때 괴경 내부에 적색 혹은 보라색 안토시아닌을 다량 함유한 유색감자는 기존 백색을 가진 일반감자에 비해 항산화, 자유레디칼 소거활성 및 항고혈압 활성이 높고, 시각적 식미감을 증대시키므로 유색감자는 기능성이 증대된 식용감자로서의 이용가치가 충분한 것으로 판단된다.

• 대한환경공학회지
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• 제32권3호
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• pp.296-308
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• 2010

Peroxone 공정은 정수처리 공정에서 기존의 염소와 오존 공정들의 여러 가지 한계점들을 극복할 수 있는 공정이다. 과산화수소와 오존에 의해 생성되는 OH 라디칼은 다양한 유기성 오염물질들에 대해 빠른 산화분해 및 높은 제거효율을 나타낸다. Peroxone 공정을 운영하는데 있어 주요 과제는 OH 라디칼 생성을 저해시키는 또는 생성된 OH 라디칼을 소모시키는 scavenger들과 공존할 때 peroxone 공정의 효율을 높일 수 있는 방안을 강구하는 것이다. Bromate와 같은 무기성 산화 부산물의 생성을 최소화할 수 있는 방안과 peroxone 공정 처리 후 염소 소독시 생성되는 염소 소독부산물들의 생성을 보다 저감할 수 있는 방안에 대해서도 많은 연구가 필요하다. 또한, 수중에 잔류하는 과산화수소에 대한 문제이다. 잔류 과산화수소를 on-line으로 측정할 수 있는 정밀한 측정장비의 개발 및 보급이 우선되어야 peroxone 공정의 운영에 있어서 안전성이 확보될 수 있다. 이러한 과제들이 해결이 된다면 peroxone 공정은 보다 다양한 목적으로 정수처리에 효율적으로 적용될 수 있을 것이다.

• Molecular & Cellular Toxicology
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• 제1권2호
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• pp.111-115
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• 2005

Ultraviolet (UV) radiation to mammalian skin is known to alter cellular function via generation of Reactive Oxygen Species (ROS), DNA damage and DNA lesions, such as pyrimidine dimmers and photoproducts, which could lead to DNA mutation if they are not repaired. In this study, we have investigated the reduction of DNA damage and of apoptosis with a particular attention to genetic effect of paeoniflorin in Normal Human Epidermal Keratinocytes (NHEK). After UVB irradiation from $10\;to\;500mJ/cm^{2}$ to NHEK, Mean Tail Moments (MTM) were increased with UVB dose increase. The greatest amount of strand breaks was induced at $500mJ/cm^{2}$ of UVB. Even at the lowest dose of UVB ($10mJ/cm^{2}$), change in MTM was detected (P<0.0001). Pretreated cell with 0.1% paeoniflorin maximally reduced the level of DNA damage to about 21.3%, compared to untreated cell. In the lower concentrations less than 0.01% of paeoniflorin, MTM had a small increase but paeoniflorin still had reductive effects of DNA damage. We measured the apoptosis suppression of paeoniflorin with annexin V flous staining kit. As we observed under the fluorescence microscopy to detect apoptosis in the irradiated cell, the fluorescence intensity was clearly increased in the untreated cell, but decreased in treated cells with paeoniflorin. These results suggest that paeoniflorin reduces the alteration of cell membranes and prevents DNA damage. Therefore, the use of paeoniflorin as a free radical scavenger to reduce the harmful effects of UV lights such as chronic skin damage, wrinkling and skin cancer can be useful to prevent the formation of photooxidants that result in radical damage.