[Release of Ca2+ ions from the sarcoplasmic reticulum of skeletal muscles after treatment with caffeine].
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.
E V
EV
Men'shikova
V B
VB
Ritov
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects*; D008274:Magnesium / Q000378:metabolism; D009132:Muscles / Q000378:metabolism*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
D005456:Fluorescent Dyes; D007473:Ion Channels; D002110:Caffeine; D008274:Magnesium; D002118:Calcium
Osvobozhdenie ionov Ca2+ iz sarkoplazmaticheskogo retikuluma skeletnykh myshts pod deĭstviem kofeina.