Ryanodine Receptor of Skeletal Muscle Is a Gap Junction-Type Channel

• DOI: 10.1126/science.2459777
• Publication Date: 2006-10-05T21:21:15Z
• Authors: Jianjie Ma; Michael Fill; C. Michael Knudson; Kevin P. Campbell; Roberto Coronado
• Keywords: 0303 health sciences; Ryanodine; Muscles; Electric Conductivity; Ryanodine Receptor Calcium Release Channel; Ion Channels; Membrane Potentials; Kinetics; Sarcoplasmic Reticulum; 03 medical and health sciences; Intercellular Junctions; Alcohols; Animals; Receptors, Cholinergic

In the sarcoplasmic reticulum membrane of skeletal muscle, the ryanodine receptor forms an aqueous pore identified as the calcium-release pathway that operates during excitation-contraction coupling. The purified ryanodine receptor channel has now been shown to have four properties usually associated with gap junction channels: (i) a large nonspecific voltage-dependent conductance consisting of several open states; (ii) an inhibition of open probability by low p H; (iii) an inhibition of open probability by calcium; and (iv) a sensitivity to blockade by heptanol and octanol but not other alcohols. This functional homology may provide an insight into the mechanism of how muscle cells transduce depolarization into an intracellular release of calcium.