【摘要】 目的探讨Na+、K+浓度对骨骼肌肌质网囊泡氧化还原系统的调控作用及对Ca2+释放通道的影响。方法提取肌质网囊泡,分别检测其在不同Na+、K+浓度下还原型辅酶Ⅰ(nicotinamideadeninednucleotide,NADH)氧化初速率、超氧产率、[3H]-ryanodine结合率和Ca2+释放速率的变化。结果高浓度的Na+、K+对肌质网NADH的氧化初速率和伴生的超氧自由基产率均有抑制作用;在[3H]-ryanodine结合实验中,高浓度的Na+、K+也压抑了NADH诱导的受配体结合的升高;同样,在Ca2+释放动力学实验中,不同浓度的K+调控了由NADH诱导的Ca2+释放初速率。结论骨骼肌肌质网膜上可能存在具有对Na+、K+浓度敏感并中介超氧自由基产生的NADH氧化还原系统,其参与调节Ca2+释放通道的活性。更多还原

【Abstract】 Objective To determine whether the effect of nicotinamide adenine dinucleotide(NADH) on activation of the RyR1 are Na~+ and K~+ concentration dependent. Method Isolated sarcoplasmic reticulum (SR) vesicles were used, initial rate of NADH oxidation, production of superoxide, ~3H-ryanodine binding rate, and Ca~ 2+ release rate were detected respectively in different Na~+ and K~+ concentrations. Result It was found that the initial rate of NADH oxidation by SR and the production of superoxide were depressed at higher concentrations of Na~+ and K~+, which implicated a salt ion concentration dependent mechanism. The ~3H-ryanodine binding assays showed that the activations of RyR1 induced by NADH were depressed at higher salt concentrations. The initial rates of Ca~ 2+ release were also modulated by different concentrations of K~+. Conclusion There is a NADH-dependent oxidase on SR, which is modulated by Na~+ and K~+. It can generate superoxide, and in turn, regulates the activation of the RyR1.更多还原