Merck, 00541-1G, Ruthenium Red

General description
Ruthenium red is an inorganic cationic dye. It is also known as ammoniated ruthenium oxychloride. It is a large coordination complex consisting of three metal atoms connected by bridging oxygens, in addition to multiple amine ligands.
Application
Inhibits mitochondrial Ca²⁺ uniporter; capsaicin antagonist; blocks VR1 vanilloid receptor-coupled ion channels.
Ruthenium red is suitable for use in light microscopy to stain pectins. It is also used to stain glycosaminoglycans by employing a two-color staining method with alcian blue. It serves as a typical basic dye at a higher pH that stains nuclei, Nissl substance, cartilage matrix, and mast cell granules. Other applications involving light microscopy include staining resin-embedded material. Ruthenium red is an important component of fixatives of the bacterial glycocalyx.
Biochem/physiol Actions
Ruthenium red inhibits mitochondrial Ca2+ uniporter. It is a known capsaicin antagonist. Additionally, it is known to block VR1 vanilloid receptor-coupled ion channels.