Ca2+ release induced by cyclic ADP ribose in mice lacking type 3 ryanodinereceptor

The action of cyclic-ADP-ribose was studied on calcium release from sarcopl asmic reticulum of skeletal muscles of neonatal and adult wild-type and RyR 3-deficient mice. cADPR increased calcium efflux from microsomes, enhanced caffeine-induced calcium release, and, in 20% of the tests, triggered calci um release in single muscle fibers. These responses occurred only in the di aphragm of adult RyR3-deficient mice. cADPR action was abolished by ryanodi ne, ruthenium red, and 8-brome-cADPM These results strongly favor a specifi c action of cADPR on RyR1. The responsiveness of RyR1 appears in adult musc les when RyR3 is lacking. (C) 2001 Academic Press.