Figure 3

Ryanodine reduces the frequency of Ca²⁺ sparks. (A) A typical experiment for the effects of ryanodine on sparks. Ryanodine decreased spark frequency by the 9^th scan. (B) Expanded line scans from (A) shows a trace in control (scan 1) and in ryanodine (scan 9). Numbers beside transients indicate sparks. (C) Ryanodine reduced the frequency of Ca²⁺ sparks but had no major effect on Ca²⁺ spark rise time or time to half-decay. Recordings in the presence of ryanodine were made at 10, 40, 70, 100, 130 and 160s after application of ryanodine. Time control experiments revealed that Ca²⁺ spark frequency, amplitude, rise time and time to half-decay were reasonably stable for nine 5 s line scans spread over 225s.