The Ryanodine receptor family consists of three different isoforms: The skeletal muscle isoform, Ryanodine Receptor type 1 (RyR1); the cardiac muscle isoform, Ryanodine Receptor type 2 (RyR2) and the brain isoform, Ryanodine Receptor type 3 (RyR3).3 The Ryanodine receptors are homotetrameric proteins. They play a key role in the mechanism of excitation-contraction coupling in striated muscle. Binding of Ryanodine to the Ryanodine Receptor causes to two major changes in the channel: a reduction in single-channel conductance and a marked increase in open state probability.nRyR2 serves as an intracellular Ca2+ channel in the SR membrane. It is predominantly expressed in cardiac muscle where it plays a central role in cardiac excitation-contraction coupling. RyR2 is also expressed in the brain
