アブストラクト（28巻1号：The Bulletin of Kanagawa Dental College）

The Bulletin of Kanagawa Dental College

English

Title　： Concentration-Response Effects of Nitric Oxide Released from Nitric Oxide Donor NOC-7 on Myofilament Function in Skinned Rabbit Cardiac Trabeculae
Subtitle　： Selective Proceedings of 34th General Meeting of Kanagawa Odontological Society, 1999
Authors　： Hirofumi Shoji, Shun-suke Takahashi, Eiichiro Okabe
Authors（kana）　：
Organization　： Department of Pharmacology and ESR Laboratory, Kanagawa Dental College
Journal　： The Bulletin of Kanagawa Dental College
Volume　： 28
Number　： 1
Page　： 74-76
Year/Month　： 2000 / 3
Article　： Report
Publisher　： Kanagawa Odontological Society
Abstract　： [Abstract] We determined the direct impact of nitric oxide (NO・) released from NO- donor 3-(2-hydroxy-1-methyl-2-nitrosohydrazino)-N-methyl-1-propanamine (NOC-7) on the functional reactivity of Triton X-100-treated rabbit cardiac fibers. NO- concentration in the experimental system was monitored by electron spin resonance technique; N-(dithiocarboxy)sarcosine-Fe2+ was used as the spin trap. NO・ released from NOC-7 reduced myofilament Ca2+ sensitivity in a concentration-dependent fashion; hill coefficient, the binding cooperativity between troponin C and Ca2+, was also decreased. The Ca2+-independent force was increased, but myofibrillar-bound creatine kinase (CK) activity was decreased, in a NO・ concentration-dependent manner. The effects afforded by NO・ were inhibited by exogenously added CK. NO・ at cumulative concentration of 0.69μM was effective in producing both enhancement of rigor contracture and decrease of myofibrillar-bound CK activity; however, Ca2+ sensitivity (pCa50) was significantly decreased at > 5.6 μM of NO・, suggesting a result of different mechanism. It can be concluded that CK may be a one of the important targets for increased NO・ formation at low molecular range in the disease state in cardiac muscle.
Practice　： Dentistry
Keywords　： Nitric oxide, Electron spin resonance, Myocardiac filament, Ca2+ sensitivity, Crossbridge, Creatine kinase activity