Study On The Effects Of Specific Physical And Chemical Factors On Redox System Of Skeletal Muscle Sarcoplasmic Reticulum

The isolated SR vesicles were used to determine whether the effects of NADH on activation of the sarcoplasmic reticulum ryanodine receptor (RyR1) were modulated by the Specific Physical and Chemical Factors: salt ions (Na⁺ and K⁺) and 50Hz 0.4mT magnetic field (MF).In this research, fluorescence spectrophotometer and UV spectrophotometer were used to measure the initial rates of NADH oxidation and the production of superoxide ions in different physical and chemical conditions; the [³H]-ryanodine binding rate, the Ca²⁺ release rate were also detected in the different physical and chemical conditions, which showed the effects of the two facts on RyR1.The results showed that the initial rates of NADH oxidation and the production of superoxide were depressed at higher concentrations of Na⁺ and K⁺, exerted a salt ions concentration dependent manners; the [³H]-ryanodine binding assays showed that the activations of RyR1 induced by NADH, were depressed at higher salt concentrations; the Ca²⁺ release initial rates were also modulated by the different concentrations of KCl; all the results indicated that the function of RyR1 were correlative with the NOX activity and the superoxide production. The effects of 50Hz 0.4mT MF were similar to those of the salt ions. The initial rates of NADH oxidation and superoxide production were obviously increased by the 30 minutes MF exposure. The rates of [³H]-ryanodines binding to the receptors and the SR Ca²⁺ release were also promoted due to the MF exposure.It can be concluded that there is a NADH-dependent oxidase on SR membrane, which can oxidate NADH and be modulated by the two physical and chemical factors. In the process of NADH oxidation, superoxide is generated; at the meantime the RyR1 is activated.