Properties of amentoflavone, a almighty caffeine-like Ca2+ releaser in ashen beef sarcoplasmic reticulum

  Amentoflavone, like caffeine, acquired a concentration-dependent access in Ca2+ absolution from the abundant atom of burst sarcoplasmic cloth of aerial ashen muscle. The Ca2+ -releasing action of amentoflavone was about 20 times added almighty than that of caffeine. The bell-shaped contour of Ca2+ assurance for amentoflavone was about the aforementioned as that for caffeine. Typical blockers of Ca2+ -induced Ca2+ absolution channels, such as Mg2+, procaine and ruthenium red, inhibited clearly amentoflavone- and caffeine-induced 45Ca2+ release.  The best 45Ca2+ absolution in acknowledgment to amentoflavone was not afflicted by caffeine, but was added added by adenosine-5'-(beta,gamma-methylene) triphosphate. This admixture added [3H]ryanodine bounden to the abundant atom of burst sarcoplasmic cloth with a abatement in K(D) but after a change in Bmax.  These after-effects advance that amentoflavone, which does not accommodate a nitrogen atom, apparently binds to the caffeine-binding website in Ca2+ channels and appropriately potentiates Ca2+ -induced Ca2+ absolution from the abundant atom of burst sarcoplasmic reticulum.