title: Ruthenium red and caffeine affect the Ca2+-ATPase of the sarcoplasmic reticulum.
abstract: Effects of ruthenium red and caffeine (a Ca2+ release blocker and an inducer, respectively) on Ca2+ uptake by sarcoplasmic reticulum (SR) vesicles and formation of the phosphorylated intermediate (EP) of the Ca2+-ATPase were studied using fast-kinetic techniques. Ruthenium red increased the rate and the maximum level of EP formation, while caffeine decreased both. Similarly, ruthenium red accelerated rapid Ca2+ uptake, while caffeine inhibited it. These drugs affected EP formation also with detergent solubilized Ca2+-ATPase. The concentrations required for half maximal effects on these functions (0.2 microM ruthenium red, 1.0 mM caffeine) are about the same as those for altering Ca2+ release. These results indicate that these reagents affect both the Ca2+-pump as well as the Ca2+ release mechanism, suggesting that the Ca2+-pump and Ca2+ release have some mechanisms in common.
authors.forename: L G
authors.initials: LG
authors.lastname: Mészáros
authors.forename: N
authors.initials: N
authors.lastname: Ikemoto
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007473:Ion Channels / Q000187:drug effects; D007700:Kinetics; D010766:Phosphorylation; D011817:Rabbits; D012428:Ruthenium / Q000494:pharmacology*; D012430:Ruthenium Red / Q000494:pharmacology*; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000201:enzymology*
chemical_list: D007473:Ion Channels; D012430:Ruthenium Red; D002110:Caffeine; D012428:Ruthenium; D000252:Calcium-Transporting ATPases; D002118:Calcium