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标题：Protective Effects of Cyclo(L-Leu-L-Tyr) against Postischemic Myocardial Dysfunction in Guinea-Pig Hearts
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作者：Kumiko Mitsui-Saitoh ; Tadashi Furukawa ; Takashi Akutagawa 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2011
卷号：34
期号：3
页码：335-342
DOI：10.1248/bpb.34.335
出版社：The Pharmaceutical Society of Japan
摘要：The protective effects of cyclic dipeptides in alcoholic beverages were investigated in the perfused guinea-pig hearts subjected to ischemia and reperfusion. Subsequently, in order to determine the importance of cyclic dipeptide structure, the effects of cyclo( L -Leu- L -Tyr) (cLY) were compared with those of the newly synthesized non-cyclic dipeptides, L -Leu- L -Tyr (LY) and L -Tyr- L -Leu (YL). After reperfusion, pressure recovery (%) in the left ventricle reached a peak of over 90% in the presence of cLY (10⁻⁶ M and 10⁻⁵ M ) (control: 22.9%). The recovery by LY and YL was significantly lower than that by cLY, and ATP levels simultaneously monitored using ³¹P-NMR were already lower during the ischemic end period than those observed with cLY treatment. In perfused mitochondrial preparations, cLY significantly inhibited mitochondrial Ca²⁺ ([Ca²⁺]_m) elevation in a similar way to that of the mitochondrial permeability transition pore (MPTP) inhibitor cyclosporin A. In vitro electron paramagnetic resonance (EPR) revealed that the active oxygen radicals quenching activity of cLY was greater than those of non-cyclic dipeptides. cLY inhibited caspase-3-induced apoptosis. The cyclic dipeptide structure inhibits opening of the MPTP by preventing [Ca²⁺]_m overload-induced apoptosis related to mitochondrial active oxygen radical accumulation in ischemia-reperfusion hearts.
关键词：cyclic dipeptide;ischemia-reperfusion injury;31P-NMR;electron paramagnetic resonance;mitochondrial permeability transition pore;apoptosis