Men'shikova E V, Ritov V B
Biokhimiia. 1986 Apr;51(4):603-11.
Using a Ca2+-selective electrode and Quin 2 and chlortetracycline fluorescence spectra, a comparative study of caffeine- and Ca2+-induced release of Ca2+ from the terminal cisterns of rabbit fast skeletal muscle sarcoplasmic reticulum was carried out. It was shown that the caffeine-induced release of Ca2+ depends on Ca2+ and Mg2+ concentration in the medium; Mg2+ inhibit, while Ca2+ stimulate this process. The caffeine-induced transport of Ca2+ is blocked by ruthenium red, tetracaine and dimethylsulfoxide. The Ca2+ release induced by Ca2+ was shown to occur in two ways, i. e., via Mg2+-dependent (inhibited by Mg2+ and caffeine blockers) and Mg2+-independent (insensitive to caffeine inhibitors, including Mg2+) routes. It was assumed that caffeine stimulates the Mg2+-dependent, Ca2+-induced release of Ca2+. The sensitivity of Ca2+ transport to caffeine testifies to the fact that about 80% of the total Ca2+ transport activity of fast skeletal muscle homogenates belongs to terminal cisterns. The total amount of sarcoplasmic reticulum membranes in the muscle makes up to 15-20 mg of protein/g of tissue.
利用钙离子选择性电极以及喹啉2和金霉素的荧光光谱，对咖啡因和钙离子诱导家兔快速骨骼肌肌浆网终末池释放钙离子的情况进行了对比研究。结果表明，咖啡因诱导的钙离子释放取决于介质中钙离子和镁离子的浓度；镁离子起抑制作用，而钙离子则刺激这一过程。咖啡因诱导的钙离子转运被钌红、丁卡因和二甲基亚砜阻断。钙离子诱导的钙离子释放表现为两种方式，即通过依赖镁离子的途径（被镁离子和咖啡因阻滞剂抑制）和不依赖镁离子的途径（对包括镁离子在内的咖啡因抑制剂不敏感）。据推测，咖啡因刺激依赖镁离子、由钙离子诱导的钙离子释放。钙离子转运对咖啡因的敏感性证明，快速骨骼肌匀浆中约80%的总钙离子转运活性属于终末池。肌肉中肌浆网膜的总量相当于每克组织15 - 20毫克蛋白质。
