| NCX , RyR 2 and SERCA 2 mRNAs ( in % of age matched 100 % CF group value ) and protein levels were quantitated in the left ventricles by slot blot and Western blot analysis , respectively . ^^^ An increased accumulation of SERCA 2 ( +36 % and NCX ( +46 % ) transcripts , but not RyR 2 , already occurred in 24 mo 30 % CF group while the 3 transcripts accumulated in 24 mo 15 % CF group . ^^^ In 4 mo rats SERCA 2 ( +26 % ) , NCX ( +35 % ) and RyR 2 ( +81 % ) mRNA levels only increased in the 15 % CF group . ^^^ |