Cyclic ADP-ribose induced Ca2+ release in rabbit skeletal muscle sarcoplasmic reticulum.
The Ca(2+)-mobilizing metabolite cyclic ADP-ribose (cADPR) has been shown to release Ca2+ from ryanodine-sensitive stores in many cells. We show that this metabolite at a concentration of 17 microM, but not its precursor beta-NAD+ nor non-cyclic ADPR at the same concentration, is active in releasing Ca2+ from rabbit skeletal muscle sarcoplasmic reticulum. The release was not sensitive to Ruthenium red (1 microM) nor to the ryanodine receptor-specific scorpion toxin Buthotus1-1 (10 microM). In planar bilayer single channel recordings, concentrations up to 50 microM cADPR did not increase the open probability of Ruthenium red and toxin-sensitive Ca2+ release channels. Thus Ca2+ release induced by cADPR in skeletal muscle sarcoplasmic reticulum may not involve opening of ryanodine receptors.
Department of Physiology, University of Wisconsin School of Medicine, Madison 53706.
J
J
Morrissette
G
G
Heisermann
J
J
Cleary
A
A
Ruoho
R
R
Coronado
D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D036563:Cyclic ADP-Ribose; D008564:Membrane Potentials; D009124:Muscle Proteins / Q000187:drug effects; D009132:Muscles / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D011817:Rabbits; D019837:Ryanodine Receptor Calcium Release Channel; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology
D009124:Muscle Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D036563:Cyclic ADP-Ribose; D000246:Adenosine Diphosphate Ribose; D002118:Calcium