RyR refractory characteristics. Figure 13: RyR refractory characteristics. (A) The stimulation protocol comprises of two consecutive stimuli S1 & S2, both of which are identical to the dyadic component (IC a,L,TT) of trace 1 (ICa,Levoked by a 10 mv clamp pulse) in Figure 7A with a peak amplitude of 6.657 pA/pF and a duration (T1) of 50 ms. These are applied with their separation in time (T2) increasing from 50ms to 250 ms in steps of 25 ms. (B) The RyR sensitive Ca2+ release channel shows refractory characteristics with an absolute refractory period of 50 ms and a relative refractory period of 250 ms. (C) The corresponding [Ca2+]
traces reflect partial RyR recovery. (D) Cytosolic calcium transient recovers completely after 250 ms. The dotted line indicates lack of RyR release when T2 = 75 ms due to insufficient RyR recovery.