Duchenne explained Glossary of research terms Sodium/calcium exchanger All our cells require small ions called sodium and calcium ions to be able to function. To prevent muscle cell damage it is very important that cells have the correct amounts of these ions. The sodium-calcium exchanger is a small protein found in cells; it removes calcium, and allows sodium to enter. When this protein is functioning well, it ensures that there is low calcium and high sodium inside cells compared to outside cells. However, research studies show that in Duchenne there is an overload of both calcium and sodium inside muscle cells, leading to damage. Potential drug treatments are being developed to regulate these concentrations in cells. One of these is called Rimeporide, being developed by the EspeRare Foundation. This drug uses a calcium-sodium protein inhibitor to decrease the amount of sodium and calcium in the muscle. In this way, it is hoped that Rimeporide will improve muscle function.