Figure 13

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 (I_{C a,L,TT}) of trace 1 (I_Ca,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⁺] _jSR 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.