• Title/Summary/Keyword: 억제환

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Modification of Endothelium on Contractile Response of Brain Vessels to Contracting Agents (혈관 수축제의 뇌혈관 수축반응에 대한 혈관근 내피세포의 역할)

  • Kook, Young-Johng;Baik, Yung-Hong;Kim, Jong-Keun;Choi, Bong-Kyu;Choi, Soo-Hyung;Kim, Yung-In
    • The Korean Journal of Pharmacology
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    • v.24 no.2
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    • pp.203-216
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    • 1988
  • To delineate the mechanisms of vasoconstriction and vasodilation in cerebral arteries the effects of some vasoconstrictors and calcium antagonists on the basilar artery (BA) and arterial circle of Willis (WC) were examined and also the role of endothelium in the action of these drugs was investigated in pigs, cats and rabbits. In pig cerebral arteries, dose-dependent contractile responses were elicited by KCI, histamine, 5-hydroxytryptamine (5-HT) and angiotensin, but norepinephrine (NE), phenylephrine (PE) and epinephrine (EP) elicited dose-dependent contractions only under pretreatment with propranolol 10-6 M. The magnitudes of maximal contractile effects of these drugs were different from each other, and 5-H~ was the largest and angiotensin the smallest. Some calcium antagonists dose-dependently inhibited KCI (35 mM)-induced contraction and the order of potency in inhibiting the contraction was nifedipine > > diltiazem > flunarizine > oxybutynin > isosorbide dinitrate (ISDN) > glyceryl trinitrate. 5-HT (10-6 M)-induced contraction was dosedependently inhibited by nifedipine but slightly inhibited by diltiazem and ISDN. In rings with intact endothelium, KCI (35 mM)-induced contraction was not affected by acetylcholine (ACh) but $PGF_{2{\alpha}}$ (lO-SM)-induced contraction was dose-dependently relaxed by ACh and adenosine. This endothelium-dependent relaxation was not affected by nifedipine (l0-6M)-pretreatment but markedly inhibited by methylene blue (50,uM)-pretreatment. In the porcine arterial rings without endothelium, ACh had no effect or even contracted the $PGF_{2{\alpha}}-induced$ contraction. However, the dosedependent relaxing effect of ACh appeared when the deendothelized porcine ring and rabbit thoracic aorta with intact endotheli urn were simultaneously suspended into a bath and this relaxing effect was also inhibited by methylene blue-pretreatment. In cat cerebral arteries, 5-HT and NE elicited dose-dependent contractile responses and ACh also produced dose-dependent contraction regardless of the existence of endothelium. ACh-induced contraction was most prominent. 5-HT (IO-SM)induced contraction was not relaxed but contracted additionally by ACh even in the intact endothelial ring. In rabbit cerebral arteries, 5-HT and NE elicited dose-dependent contractile responses and 5-HT-induced contraction was more prominent. In the intact endothelial preparations, 5-HT (lO-s M)-induced contraction was markedly relaxed by the addition of ACh( IO-SM) and this endothelium-dependent relaxing effect was inhibited by atropine (l0-7M)-pretreatment but notaffected by diltiazem (l0-6M)-pretreatment. These results suggest that ACh elicits endotheliumdependent relaxing effect mediated by muscarinic receptors in cerebral arteries of pig and rabbit, and that ACh acts as vasoconstrictor in cat cerebral artery.

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Tyrosinase Inhibitory Activity of Macrolepiota procera (큰갓버섯(Macrolepiota procera)의 Tyrosinase 효소활성 저해효과)

  • Kwak, Jung-Hoon;Han, Yeong-Hwan
    • The Korean Journal of Mycology
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    • v.38 no.2
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    • pp.202-204
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    • 2010
  • Inhibitory effect on tyrosinase activity and melanogenesis of the mycelia and mycelial culture broth of Macrolepiota procera were investigated. The methanol fraction of culture broth showed 56.6% of tyrosinase inhibitory activity and its IC50 was 8.78 mg/ml. Using Streptococcus bikiniensis for melanogenesis in vitro, the methanol extract of mycelia showed 94.0% inhibition of melanogenesis.

Antigenotoxic Effects of Phellinus linteus and Agaricus blazei Murill Extracts (상황버섯(Phellinus linteus)과 아가리쿠스버벗 (Agaricus blazei Murii) 추출물의 유전독성 억제효과)

  • 지정환;김미남;정차권;함승시
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.29 no.3
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    • pp.513-517
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    • 2000
  • 상황(Phellinus linteus) 및 아가리쿠스(Agaricus blazei Murill) 버섯으로부터 얻어진 메탄올 추출물과 이들 용매분획물에 대하여 마우스의 골수세포를 이용한 소핵 실험을 행하여 MNNG에 대한 유전독성 억제효과를 실험 하였다. 상황버섯 메탄올 추출물은 MNNG에 의한 소핵생성에 대하여 10.6~75.6%의 억제효과를 나타내었다. 또한 각각의 분획물의 경우 80mg/kg에서 에틸 아세테이트, 디에틸에케르, 부탄올, 클로로포름 그리고 물층이 각각 81.3,78.1,75.6,72.4 그리고 63.4%의 유전독성 억제 효과를 나타내었다. 아가리쿠스버섯 메탄올 추출물의 유전 독성 억제효과에서 양성대조군에 비하여 80mg/kg 투여시 86.2%의 억제효과를 나타내었으며, 디엘티에테르, 에틸 아세테이트, 클로로포름, 부탄올 그리고 물층 분획물의 경우 80mg/kg 투여시 86.2,81.3,78.1,69.9 및 61.8%의 억제효과를 나타내었다. 이상의 연구 결과에서와 같이 상황버섯과 아가리쿠스버섯의 추출물과 분획물들은 높은 유전독성억제효과를 나타냄으로서 건강식품으로서의 개발과 고부가가치의 의약품으로서 개발가능성을 가진 대단히 유용한 버섯임을 알 수 있었고, 다음 단계의 실험으로 이러한 생리활성을 나타내는 부분만을 분리, 정제하여 추가적인 검색 및 활용방안에 대하여 충분한 연구가 이루어져야 한다고 사료된다.

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수요 억제 중심의 일괄적인 정책에 부동산 시장 멍든다

  • Go, Cheol
    • 주택과사람들
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    • s.199
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    • pp.26-27
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    • 2006
  • 2006년 부동산 시장은 개발이익환수제와 주택담보대출 규제를 강화하는 3 · 30 대책 이후 마지막에 발표된 주택 공급확대 방안을 골자로 한 11 · 15대책으로 혼란스러웠다. 이에 2006년 부동산 시장의 동향과 문제점을 통해 시사하는 바를 알아봤다.

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