Rapid Ag+-induced release of Ca2+ from sarcoplasmic reticulum vesicles of skeletal muscle: a rapid filtration study.
Using a rapid filtration method, we show that Ag+ is able to trigger Ca2+ release from sarcoplasmic reticulum vesicles at a rate as fast as that induced by Ca2+ itself. The Ag+ concentration dependence of the rate constant of Ca2+ release presents a bell shape, similar to that of Ca2+-induced Ca2+ release, with a maximum at 30 microM free Ag+. The rapid phase of Ca2+-release induced by Ag+ is activated by millimolar ATP and inhibited by 5 microM ruthenium red. Moreover, micromolar Ca2+ produces a shift of the Ag+ concentration dependence of the Ca2+ release rate. All these results suggest that Ag+ acts on the same sites as Ca2+ to regulate the release of Ca2+.
Moutin
M J
MJ
Laboratoire de Biophysique Moléculaire et Cellulaire, U.R.A. 520 du CNRS, DRF/CEN-G, Grenoble, France.
Abramson
J J
JJ
Salama
G
G
Dupont
Y
Y
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005374:Filtration; D066298:In Vitro Techniques; D011817:Rabbits; D012430:Ruthenium Red / Q000494:pharmacology; D012519:Sarcoplasmic Reticulum / Q000187:drug effects* / Q000378:metabolism; D012834:Silver / Q000494:pharmacology*
D012430:Ruthenium Red; D012834:Silver; D000255:Adenosine Triphosphate; D002118:Calcium