Excitation-contraction coupling in skeletal muscle: comparisons with cardiac muscle.
1. The present review describes the mechanisms involved in controlling Ca2+ release from the sarcoplasmic reticulum (SR) of skeletal muscle, which ultimately regulates contraction. 2. Comparisons are made between cardiac and skeletal muscle with respect to: (i) the role of the dihydropyridine receptors (DHPR) as Ca2+ channels and voltage-sensors; (ii) the regulation of the ryanodine receptor (RyR)/Ca2+-release channels in the SR; and (iii) the importance of Ca2+-induced Ca2+ release. 3. It is shown that the key differences of the skeletal muscle Ca2+-release channel (RyR1), namely the increase in its stimulation by ATP and its inhibition by Mg2+, are critical for its direct regulation by the associated DHPR and, consequently, for the fast, accurate control of skeletal muscle contraction.
Lamb
G D
GD
Department of Zoology, La Trobe University, Bundoora, Victoria, Australia. zoogl@zoo.latrobe.edu.au
D000818:Animals; D002118:Calcium / Q000378:metabolism; D006321:Heart / Q000502:physiology*; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*
D002118:Calcium