Ruthenium red is a strong inhibitor of Ca2+ transport in mitochondrial, in erythrocyte membrane and in sarcoplasmic reticulum (SR) of rabbit skeletal muscle, with the Km of 4.5 μM and 2.0 mM for the two Ca2+-binding sites [1].
By kinetic experiments, there are two high-affinity Ca2+-binding sites face the cytoplasmic portion of the SR membranes, which are located in helical segments clustered in the transmembrane domain of Ca2+-ATPase, forming a Ca2+ channel.
SR vesicles were incubated with 10 μM-45Ca2+ and various ruthenium red concentrations for 15 min before being filtered for 45Ca counting. The titration curve of Ca2+ binding showed two well-differentiated saturating effects with the Km of 4.5 μM and 2.0 mM for the two Ca2+-binding sites. The ability of SR vesicles to bind Ca2+ was decreased by micromolar ruthenium red concentrations [1].
In the investigation of the ability of inhibiting caspsaicin-induced plasma extravasation in the rat trachea, ruthenium red can reduce the amount of plasma extravasation in dose-dependently, with a dose of 5 μmol/kg of completely inhibiting [2].
Reference:
[1] Corbalan-Garcia S, Teruel J A, Gomez-Fernandez J C. Characterization of Ruthenium Red-binding sites of the Ca2+-ATPase from sarcoplasmic reticulum and their interaction with Ca2+-binding sites [J]. Biochem J. 1992, 287(3): 767-774.
[2] Brokaw J J, White G W. Characterization of Ruthenium Red as an Inhibitor of Neurogenic Inflammation in the Rat Trachea [J]. Gen Pharmac. 1995, 26(2): 327-331.
