Fig. 3. Effect of type 3 RyR knockdown or RyR inhibition on global Ca²⁺ signaling upon activation of the cADPR/Ca²⁺-signaling system. T cells [control clone E2 (a,c) or type 3 RyR-knockdown clone 25 (b,d)] were loaded with Fura-2/AM and analyzed by single-cell Ca²⁺ imaging as described in the Materials and Methods. cADPR was microinjected (a,b; pipette concentration 20 µM) or cIDPRE was added extracellularly (c,d; final concentration 500 µM) as indicated. Inhibitors were microinjected directly before start of the measurement: (c) Ruthenium Red (RuRed; pipette concentration 10 µM). Data acquisition rate was 0.1 ratios/second before OKT3 addition, and 2 ratios/second thereafter. Characteristic tracings out of 15-24 cells are displayed.