The present study established a model of RyR 2 knockdown cardiomyocytes and elucidated the role of RyR 2 in aconitine-induced arrhythmia. Cardiomyocytes were obtained from hearts of neonatal Sprague-Dawlay rats. siRNAs were used to down-regulate RyR 2 expression. Reduction of RyR 2 expression was documented by RT-PCR, western blot, and immunofluorescence. Ca 2+ signals were investigated by measuring the relative intracellular Ca 2+ concentration, spontaneous Ca 2+ oscillations, caffeine-induced Ca 2+ release, and L-type Ca 2+ currents. In normal cardiomyocytes, steady and periodic spontaneous Ca 2+ oscillations were observed, and the baseline [Ca 2+ ] i remained at the low level. Exposure to 3 μM aconitine increased the frequency and decreased the amplitude of Ca 2+ oscillations; the baseline [Ca 2+ ] i and the level of caffeineinduced Ca 2+ release were increased but the L-type Ca 2+ currents were inhibited after application of 3 μM aconitine for 5 min. In RyR 2 knockdown cardiomyocytes, the steady and periodic spontaneous Ca 2+ oscillations almost disappeared, but were re-induced by aconitine without affecting the baseline [Ca 2+ ] i level; the level of caffeine-induced Ca 2+ release was increased but L-type Ca 2+ currents were inhibited. Alterations of RyR 2 are important consequences of aconitinestimulation and activation of RyR 2 appear to have a direct relationship with aconitine-induced arrhythmias. The present study demonstrates a potential method for preventing aconitine-induced arrhythmias by inhibiting Ca 2+ leakage through the sarcoplasmic reticulum RyR 2 channel.

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In this paper, the research status and the significance of the simulation technology were discussed, and the necessity introducing the simulation technology into the agricultural machinery design was analyzed. Through the material kinematics simulation in processing, both the component kinematics simulation and the system dynamic simulation of the agricultural machinery, a specific application of the simulation technology in the agriculture machinery design was displayed. Application of the simulation technology in the agricultural machinery design has a vital significance for enhancing their design and development ability, improving their product performance, as well as promoting new agricultural machinery and the agricultural mechanization.