Fig. 1.
Single RyR2 channel response to changes in luminal [Ca2+] in the absence of added redox reagents. (A) Records of 3 s of single channel activity at +40 mV, where channel opening is upward from zero current (‘C’, continuous line) to maximum open conductance (‘O’, broken line) with a cytoplasmic [Ca2+] of 1.0 µM. Descending from the upper trace, the data show activity following luminal perfusion with a 0.1 mM Ca2+ solution followed by stepwise increase in luminal [Ca2+] – 0.5 mM, 1 mM and 1.5 mM. Open probability (Po) values for each recording are shown. (B–E) Mean data for Po, n = 17–24 (B); mean open time (To), n = 12–15 (C); mean closed time (Tc), n = 12–17, (D); and mean open frequency (Fo), n = 12–17 (E). Error bars show ±s.e.m.; *P<0.05 (versus the value at 0.1 mM Ca2+).